There is a good tutorial at gimptalk on this in gimp:
http://www.gimptalk.com/forum/cuttin...tool-t769.html

(I apologize for the title... for some reason people there call "removing the background of an image" "rendering" as opposed to the conventional CGI use of the term rendering, which confused the heck out of me.... I think it comes from the PS selection tool having the word render in the dialog...)

-Rob A>