Hidden signatures: how to do it?

For the first time I am selling my work over the net. Now I'm in the habit of just signing it and handing it over but since I can't exactly do that with the same effectivness with digital pictures as I can with acrylics/oils it won't quite do. So if anyone can give me tips on how to make an effective hidden sig. I would appreciate it.

Thanks.

you can buy a watermarking script for PS I do beleave you can always brand your work like we do here with your name and everything

create yor own. make a design in PS add it as a layer with a relatively low opacity and place it unobtrusivelyin the pic. it's cheeper and more flexable. pt it in several places onthe pic jst to be sure.

i usually use this for a sig:
http://img.photobucket.com/albums/v6...turesmall1.gif

i'll put it in about eight places on the pic so it's hard to get rid of without making it obvious that it has been edited. different orientations and sizes help too ;)