@rbates has a great (as always) screencast on Jeweler and Gemcutter.

img http://img.skitch.com/20091012-rrf7756fn2kpqeqbx7qukg8xrn.png http://railscasts.com/episodes/183-gemcutter-jeweler

Check it out and give Gemcutter a try!

(mg looks like another good tool to help you create gems, too (though I haven’t used it).)