Always play to your strengths and make it be about them (not you). Be prepared to discuss why going with a small firm gives them an advantage. (like Shawn said ... excellent answer)

I recommend http://websupportteam.com/ for small projects. They provide quick turnaround and excellent customer service. I have used this service for a couple of years and will only add that you must provide very specific instructions.

Hope this helps. Please feel free to get in touch for more information.

Some great answers here. I would also add that you could spend some time on https://angel.co/ to research compensation vs equity at other startups, and perhaps begin to build a community of entrepreneurs and mentors.