Any chance, did you install the gstreamer from packman?
It happened to me 3-days ago, I replace the oss gstreamer with the packman version and cheese suddenly stop working with my webcam, while luvcview works. When I reverted back to the opensuse 1.2 gstreamer, cheese went back to normal.
Same for me with 11.2 x86_64 on Shuttle with a Creative Webcam Notebook (041e:401f). It is ok with mplayer and luvcview, and just color bars with cheese.
By default, image is awful through skype but becomes good after the work around given on the Skype forum.
Cheese is a gnome application, but I don’t see why it would not run on KDE ?