Public test realm is up and both WowInsider and mmo-champion have a list of all documented and undocumented changes in the build.
Highlights include:
Players may now create death knights on any realm once they reach level 55.
Racial restrictions on mounts have now been lifted. Night elves on mechanostriders? Tauren on raptors? You’re not seeing things.
Tapping: All [...]
Mmo-champion has come across an interesting FAQ article on blizzards support site.
Customisation will cost $15 and does not include race or class it does however include the characters name. So in effect instead of just changing the name of a character now, you can also change the race and facial features.
More details in the [...]
Mmo-champion has a list of changes in the latest beta build.
You can read the full list here.
Mmo-champion has an article up listing most of the new mounts available in WotLK
No real details on how to obtain most of them (yet) however.
You can check them out along with screen shots here.
MMO-Champion has a list of the latest Eye of Eternity Loot (EEL).
The list is not complete and is still being updated as more items are found, so check back later.