RACES(listed are the changes, all other characteristics are assumed to still be in place)
Half-Orcs: +2 Str, -2 Int (no charisma penalty).  Half-orcs may treat the orc double-axe as a martial weapon instead of an exotic weapon.

Orcs:  Proficiency in all simple weapons (the description in the MM says this, but the SRD and the stat block at the end don't mention it).  Orcs treat the orc double-axe as a martial weapon.

Elves: Favored class is now Bard.

Half-elves: Get elf weapon proficiencies.  Favored class (Any), means any they choose at any time, not just the highest current one.

Humans:  Favored class (Any), means any they choose at any time, not just the highest current one.

Gnomes:  Favored class is now Wizard.

Gnolins:  Is a playable race with a LA +1.

Kobolds:  Can use a slightly modified version that gives claws and bite attacks, as well as the ability to be treated as smaller when it is to an advantage (squeezing through tunnels).

Sub-races:  Generally the number of sub-races will be severely restricted.  Most sub-races will just be sub-cultures.  Thus high elves and wood elves have the same base stats, they just have cultural differences.  Some sub-races will exist if their role can’t be filled with the basic version, such as aquatic elves.

Other MM Races

Players may play just about any humanoid or monstrous humanoid race as well as some giant races. If the race has racial hit dice, they must gain these first before class levels. If the race has a level adjustment, the PC takes a -1 on skill checks, ability checks, attack rolls, saving throws, and -5 hit points (after con bonus added in, minimum 1 per HD) per point of level adjustment that PC's experience is below.

The PC will be considered an apprentice (see pp. 40-41 in 3rd edition DMG) in the first PC/NPC class they intend to take after they have overcome their racial HD and level adjustment. The racial HD are considered to be their primary and favored class.

So for example: Player Bob wants to play a troglodyte fighter. Looking at the MM we see that troglodytes have 2 racial hit dice and a +2 level adjustment. So the first five levels for Bob's troglodyte would look like:
Level 1: 1 racial HD, -2 on skill checks, ability checks, attack rolls, saving throws, and -10 hit points, apprentice-level benefits for fighter (+1 Fort, 1 *bonus feat, weapon/armor proficiencies)
Level 2: 2 racial HD, -2 on skill checks, ability checks, attack rolls, saving throws, and -10 hit points, apprentice-level benefits for fighter (+1 Fort, 1 *bonus feat, weapon/armor proficiencies)
Level 3: 2 racial HD, -1 on skill checks, ability checks, attack rolls, saving throws, and -5 hit points, apprentice-level benefits for fighter (+1 Fort, 1 *bonus feat, weapon/armor proficiencies)
Level 4: 2 racial HD, apprentice-level benefits for fighter (+1 Fort, 1 *bonus feat, weapon/armor proficiencies)
Level 5: 2 racial HD, 1 class level (with full benefits of 1st level fighter)

*This is the bonus feat for his first level of fighter.