Aside from the obvious new dailies, you will now be getting experience from gathering professions, archeology. How much you get seems to depend on your level, your skill level and the level of the thing you are gathering.
Some examples for a level 80 would be:
- new dailies - around 23.000xp
- level 80 mob kills - around 4-5000xp
- intro level cataclysm herbs - 4-5000xp
- archeology fragment - around 23.000xp
- archeology site cleared - around 70.000xp
A good idea might be to get 25 daily quests from Wrath endgame and complete all of them, but not to turn them in. That way, you get a nice start once the level cap goes up to 85. Blizzard might decide to stop you from doing this, though, so don't put all your hopes into something like that.