If you're in NYC, Time's Up has free bike repair classes. Don't have the web site on me, but google the name. They're a non-profit, environmentally conscious bike co-op, if you will. Anyway, Mondays at 6:30pm they have ladies' bike repair night. Tuesdays is co-ed, and Thurs they allow you to work on your bike using their equipment (like a free repair space).
I only went to one, and it wasn't organized terribly well, but I'm definitely going back. I think they are now dedicating Tuesdays to specific issues, so check out the calendar on the Web site. Cheers!