Making this post just to update when there is a new beta build, and who has talent changes for the build, if any. Figure this is better than making 3+ posts in each class' thread. I'll add a new reply each time there is an update, rather than just editing the post each build.

And to start it all off, Cataclysm Beta - Build 12539.
Death Knights: Minor changes to how some Unholy Talents work. No point changes.
Hunter: Counterattack no longer costs mana, Survival Talent.
Paladin: Lots of significant changes in all 3 trees.
Priests: Update to Healing Prayers talent in the Holy tree.
Rogues: Update to Assassination Talents. Slight update to Shadowstep mechanics in Subtlety tree.
Shaman: Changes on early Enhancement/Elemental Talents.
Warlock: Significant changes in Demonology/Destruction trees.
Warrior: Significant changes to Fury and Protection trees.

Cataclysm Beta - Build 12604
Major talent updates/changes for most classes this build.
Only slight updates for Hunters, Priests, and Rogues.

Cataclysm Beta - Build 12644
Significant changes for all three mage specs
Significant changes for all three warrior specs