Fine, but the next round of beer is on you.
There isn't much difference between the races right now, as a lot of racial abilities aren't in.
Horde
Orc
Classes Allowed: Hunter, Warlock, Warrior, Shaman, Rogue
Starting point: The Den, in southern Durotar.
Racial Abilities: (I don't know)
Tauren
Classes Allowed: Hunter, Shaman, Warrior, Druid
Starting point: Camp Narache, in south-eastern Mulgore.
Racial Abilities: Plainsrunning (trainable at level 40, as Taurens cannot have a Mount)
Troll
Classes Allowed: Hunter, Warrior, Shaman, Priest, Mage, Rogue
Starting point: The Den, in southern Durotar.
Racial Abilities: (I don't know)
Undead
Classes Allowed: Warrior, Priest, Mage, Warlock, Rogue
Starting point: Deathknell, in south-eastern Tirisfal Glades.
Racial Abilities: Underwater Breathing, Immune to most mind-influencing spells.
Alliance
Human
Classes Allowed: Paladin, Warrior, Priest, Mage, Rogue, Warlock
Starting point: (I forgot)
Racial Abilities: They used to get more skill points, but skill points no longer exist. Unknown, at this point.
Dwarves
Classes Allowed: Hunter, Warrior, Mage, Paladin, Priest, Rogue
Starting point: Anvilmar, in south-western Dun Morough.
Racial Abilities: Resistant to Cold based attacks/spells, and "Treasure Finding" (though I don't know how it works).
Night Elves
Classes Allowed: Hunter, Warrior, Priest, Druid, Rogue
Starting point: Teldrassil, an island at the top of Kalimdor (main Horde continent).
Racial Abilities: (I don't know)
Gnomes
Classes Allowed: Warrior, Rogue, Mage, Warlock
Starting point: Anvilmar, in south-western Dun Morough
Racial Abilities: Really short? (I don't know)