What kinds of parts? If you can be more specific, I can help point you in the right direction. I've got an ever-increasing collection of vintage Singers I'm fixing up, and have learned that some parts are readily available while others are tricky to find.
If you're looking to identify machines visually, I've written up a guide to some of the more common Singers here:
http://vssmb.blogspot.com/2011/07/vi...g-singers.html
Steve's links should also be helpful, and others will surely chime in with more; there's a lot of information on the web.