gigadelik which one of those is your webcam? Theres a link my previous post to a list (http://siv.mysite.wanadoo-members.co.uk ... sbdevs.txt
Google the model and linux, this will show you if anyone has managed to set up your cam before on linux.
Look for any references to the driver that you need, probably gspca, which is incuded in sabayon 3.4 L3 (not sure about others).
Then check here
which shows weather your cam is supported by the gspca driver, it also has lots of useful information, i havent got time to look though it but theres a HowTo and other things.
# modprobe gspca
then plug in cam, and see if you can get any input.