On the Atari forums, a member has asked whether UT2007 will arrive on PC and whether it will be a launch title for PS3. this is what they said:
"PC first. We're not scheduled to be a ps3 launch title, not certain where those news sites are getting that from. There will be a pre-release demo (on the PC at least)."
So there you have it, UT2007 will come out for the PC first, and will not be a launch title for the PS3. There will also be an upcoming demo for the game .
Keep your eyes peeled for the demo!