I checked with Steve Polge and he said that YES we are supporting keyboard and mouse in Unreal Tournament 3 on PS3. He is confident we are doing it in a way that will be balanced without feeling "gimped" for either side. We'll also allow people to choose whether or not they want to allow mixed controller vs. keyboard/mouse games or not.
I think you guys are going to love UT3!
More details to come later.