Where can I find a co-founder?

The best way to meet a co-founder is to go to their watering holes.  People who want to start companies:

• Will take entrepreneurship classes to learn skills
• Will attend area meetups to get involved in the local entrepreneurship landscape
• Will take part in various startup competitions

The Hitchhiker's Guide to Boston Innovation is a great place to find out what's going on in the greater Boston area.