Here's what changes in the 1.1 patch:
Scrin Mastermind's Teleport Units ability maximum range reduced. GDI Engineers, Nod Saboteurs, and Scrin Assimilators can no longer capture structures when under the effects of the Scrin's Phase Field ability.
Improved video playback on low-end system configurations.
Scrin Storm Column cost / build time increased to 3,000 credits / 30 seconds. Scrin Buzzer health reduced to 75 and weapon damage changed to SNIPER.
Fixed an error that would occasionally result in a crash in Nod vs. Nod matches on the multiplayer map Deadly Sertao. Fixed issues with automated map transfer ability in multiplayer. Fixed an error that would sometimes cause a Commentator's telestrator drawings to not erase when intended during BattleCast matches. Fixed issues with replay file playback. Fixed placeholder text and chat log errors with the Comrade in- game chat window.
References to Nod's "Avatar Warmech" unit have been changed to "Avatar". Users can now turn off the Kane Edition skins
And there's also a note that patch 1.2 for C&C3: TW is expected somewhere in late April. The 1.2 patch will feature some balance changes, alternate mouse setups, bug fixes and a couple of new maps.
The patch can be downloaded through the automatic update engine of C&C3.