transparent background from a B&W *.ps, *.eps

[buddycat]

Does anyone know how to convert the white background in a
black-and-white postscript file into a transparent background,
then convert that file into a format that can be put on a web page?

I'd like to do this without investing into a commercial program. Any ideas for shareware (e.g. GSview) or editing the *.ps file?

Thanks