hey,
erm, ... please, no caps here, it's not very nice
so... you see User CP in the upperleft corner?
Click it and go to Edit Profile.
Than under Signature, you have "Upload Custom Signature Image"
Click on that.
There, you have "upload sig" and "browse", right?
Well, hit browse and select the pic you want, than hit "upload sig"... than you get a code.
ie: http://www.killermovies.com/forums/images/user_sigs/customsig_544.gif )
so, that code, copy it ENTIRELY, go to the "Edit Profile" again and in "signature" you place that code you got.
Done