The above link has a bit of info about what 4.03a will do for us. I thought I'd list some of the info for those too lazy to click the link/read
What's in Patch 4.0.3a
Sammew posted an interesting list of the features you should and should not expect in Patch 4.0.3a on the official forums. Zarhym also jumped in, and announced a 20% reduction to the XP required to gain levels from 71 to 80.
What is not in:
* Creating worgen/goblin characters
* Worgen/Goblin start zones
* Archeology
* Professions past 450 (Illustrious Grand Master)
* Guild leveling
* Guild achievements
* Eastern Kingdoms/Kalimdor flight
* New Zones (80+)
What is in:
* Portals in Dalaran/Shattrath Removed
* Class trainers in Dalaran where portals once were
* New race-class combinations (excluding worgen/goblin)
* New Gnome/Troll starting areas
* Changes to existing zones
* New cata load screens
* New cata intro cinematic
* New cata login screen
* New music
* City Quartermasters, with rep tabards
* Bug fixes
* Class balancing
* Druids, paladins, priests, and shaman will have their talent trees reset
* Experience required to gain levels 71 through 80 is being reduced by 20%
* New tamable hunter pets (Monkey, fox, dog, and beetle, as well as new skins for existing pet classes.)
Portals removed from Shattrath and Dalaran
Blizzard doesn't want you to use Shattrath and Dalaran as portal hubs anymore, the latest beta update removed all the portal to the cities and replaced them with class trainers.
Race / Class Combinations
This patch will allow you to pick new classes with the existing races! Worgens and Goblins will not be unlocked with this patch, and will only be available on December 7th for people who bought the expansion.
Chart of race class combos.
They have more information on MMO-champion but that's the info for most of the immediate changes.
