I really dig this little app!
Easy Picture2Icon can create transparent icons in multiple sizes with only a couple quick and easy steps. Import your BMP, GIF, JPG or PNG image that you want to turn into an icon and click save. It's that easy!
It's free, but doesn't contain help files. I can't really see why you'd need them though, as the program is pretty self-explainitory. The download is available here!
If you enjoy using this nifty little app, make sure you thank the author by writing to info@syrsan.com.