If you're SF, I would highly recommend the local evening meetups. They are full of founders at a variety of early stages of their journey. Last night at a meetup at Github I met the following types: Series B+, Seed+, pre-seed, pre-product, just out of college started a company, not quit job yet etc.
If you're in some other city, try to find our where the local founders hangout - this might be meetups, specific universities, specific incubators etc.