Icewind Dale 2 will be using 3E feats. The feats are a number of passive and active abilities than can be employed by a wide variety of characters. Unlike skills, feats typically do not have "levels"; they usually give a single ability to the character that gives them additional options or bonuses. Fallout's "perks" are a good analogy.

All characters start with one feat. Human characters start with an additional feat. Fighters start with another additional feat. Characters gain an additional feat at 3rd, 6th, 9th, etc. level. Some classes, like fighters and rangers, also gain bonus feats as they advance. In fact, the fighter class' bread and butter is the use of feats in combat.

Often, feats have prerequisites. If a character does not have the prerequisites required for a feat, he or she cannot take it. Here is a preliminary list of SOME feats from the game:

Aegis of Rime - Grants 5 Cold Resistance (permanent), and a +20% increase to all Cold Damage done.
Ambidexterity - Lowers penalties for two-weapon fighting.
Aqua Mortis - Grants 5 Acid Resistance (permanent), and a +20% increase to all Acid Damage done.
Armored Arcana - Taking this feat reduces the chance of arcane casting failure from armor by 5%. It may be taken up to three times.
Arterial Strike - Allows a rogue character to sacrifice 1d6 points of sneak attack damage to inflict a bleeding wound that causes damage over many rounds.
Bullheaded - +1 to all Will saves and +2 bonus on all Intimidate checks.
Combat Casting - Grants a bonus to concentration checks for spellcasters.
Dash - Increases movement by 1.
Deflect Arrows - Grants a bonus vs. missile attacks.
Dirty Fighting - On a critical hit, the character causes Blindness (50% chance) or Slow (50% chance) for five rounds unless a save vs. death is made. Undead, golems, and elementals are immune to these effects.
Discipline - +1 bonus to Will saves, +2 bonus to Concentration checks.
Dodge - Grants a +1 miscellaneous AC bonus.
Envenom Weapon - Envenoms the character's currently equipped weapon. The first successful attack with the weapon forces a Fortitude save (20 DC) or the target temporarily loses 1d6 points of Constitution. One round later, the target must make a second Fortitude save (20 DC) or lose an additional 1d6 points of Constitution. The Constitution loss lasts for 10 rounds.
Expertise - Allows the character to take a penalty of -1 to -5 (or max of BAB) to hit with a melee weapon to gain a bonus of +1 to +5 (generic) to their AC.
Extra Rage - Barbarian gets an extra rage per day.
Extra Shapeshifting - Allows a druid with shapeshifting to gain an additional use per day.
Extra Smiting - Allows a paladin to gain an additional Smite Evil use per day.
Extra Turning - Gives a Paladin or Cleric an Extra Turning.
Fiendslayer - Allows a paladin to gain a +3 bonus to hit and damage against chimeras, demons, dragons, and half-dragons.
Great Fortitude - +2 bonus to Fortitude saves.
Hamstring - Allows a rogue character to sacrifice 2d6 points of sneak attack damage to reduce the target's movement by 50%.
Heretic's Bane - Allows the character to gain a +3 bonus to hit and damage against clerics and druids.
Heroic Inspiration - When the character drops below 50% hit points, he or she gains a +1 bonus to hit, damage, and saving throws.
Improved Critical - Grants a +1 bonus to critically hit.
Improved Turning - Adds +2 to the number of HD that can be affected per turning attempt.
Iron Will - +2 bonus to Will saves.
Lightning Reflexes - +2 bonus to Reflex saves.
Lingering Song - When a bard stops playing, the effects of his or her song last an additional 2 rounds.
Luck of Heroes - +1 bonus to all saving throws.
Maximized Attacks - All attacks do maximum damage for 10 seconds. 1/Day.
Mercantile Background - Character gains an additional 10% bonus to mark up and mark down in stores.
Power Attack - This feat allows the character to take a penalty to hit in order to increase his or her damage with melee weapons.
Point Blank Shot - Reduces the penalty for firing in melee from -8 to -4.
Rapid Shot - Character takes a penalty of -2 to all attack rolls to make an additional missile attack at their highest BAB. E.g.: Frank gets three attacks with his bow at +13/+8/+3. When he enables Rapid Shot, he has four attacks at +11/+11/+6/+1.
Scion of Storms - Grants 5 Electrical Resistance (permanent), and a +20% increase to all Electrical Damage done.
Spell Focus (Enchantment, Invocation, Necromancy, Transmutation) - Add +2 to the Difficulty Class (DC) for all saving throws against spells from this school of magic. Rank 2, "Greater Spell Focus" provides a +4 to the DC. This does not stack with rank 1's +2.
Spell Penetration - +2 to bonus to caster level checks to beat a creature's spell resistance. Rank 2 is called "Greater Spell Penetration" It grants a +4 bonus to caster level checks to beat a creature's spell resistance. This does not stack with Spell Penetration, in other words having this and normal Spell Penetration only gives a +4 bonus and not +6.
Spirit of Flame - Grants 5 Fire Resistance (permanent), and a +20% increase to all Fire Damage done.
Strong Back - Carry weight increased by 50%.
Subvocal Casting - The caster can ignore the effects of Silence on spellcasting.
Toughness - +3 hit points (can be taken multiple times)
Two-Weapon Fighting - Lowers penalties for two-weapon fighting.
Weapon Finesse - Allows a character to use his or her Dexterity bonus when making attack rolls with daggers and shortswords.

In addition to the feats listed above, there are also weapon and armor feats. The weapon types are divided into simple and martial categories:

Simple
SW: Crossbow
SW: Mace
SW: Missile
SW: Quarterstaff
SW: Small Blade

Martial
MW: Axe
MW: Bow
MW: Flail
MW: Great Sword
MW: Hammer
MW: Large Sword
MW: Polearm

Most non-warrior characters (wizards, sorcerers, rogues, clerics, etc.) start with proficiency (one star) in most or all simple weapons. Warrior characters (barbarians, paladins, rangers, fighters) start with proficiency in all weapon types.

Increasing an individual weapon proficiency is the equivalent of taking the feat Weapon Focus, which grants +1 to hit. Characters with 4 or more levels of fighter may also take Weapon Specialization (three stars), which grants an additional +2 to damage. Elf characters start with a free proficiency in either MW: Bow or MW: Large Sword.

Armor proficiencies reduce the inherent penalties for wearing armor. Although any character can wear armor, most will not want to wear armor. Wearing armor causes chances of arcane spellcasting failure, penalizes thief skills, and can even cause penalties to hit for those without the proper feats.

The following list breaks down armor types. The first column lists the types of armor. The second column lists the chance for arcane spell failure. The third column lists penalties to thief skills (which may be translated into 3E 5% into 1 values). The fourth column lists the maximum dexterity bonus to AC that a character may receive while wearing that armor type.

If a character does not have the appropriate armor feats (light, medium, heavy, and shield), he or she gains additional penalties for wearing that armor. Fighters, clerics, and paladins start out with all armor proficiencies. Rangers, druids, barbarians, and rogues start out with less. Wizards and sorcerers have no armor proficiency.

We are also translating some of the previously used kit powers into feats (Envenom Weapon, Trick Shot, etc.).

To be honest, meta-magic feats are unlikely. They would be quite difficult to implement, I am sorry to say. I don't want to get your hopes up about them. Spell Penetration is a possibility.

And here is something about the implementation:
Basically, there is one big function through which most baby functions go when they check class IDs. Normally, they say, "HEY, ARE YOU A FIGHTER? NO? OKAY. HEY, ARE YOU A MAGE? NO? OKAY. HEY, ARE YOU A FIGHTER/MAGE? NO? OKAY." and so on.
Instead of adding multiclass class IDs, we aren't using multiclass class IDs at all. The class levels contain their own IDs. When the functions make their checks, they just check for the core class IDs after looking through all of the class level fields a character has. If any of them return true for that check, it makes calculations based on what is present.
At least, that's the basic idea.