As an ex-deal lawyer and the founder of www.avvo.com (where lawyers will answer your legal questions for free btw), I urge you to have a seasoned venture lawyer at your side from the outset. Most firms will forego fees until your first round of financing, so there is really no downside. The real downside is trying to play lawyer and failing to adequately protect yourself and your company.
Mark Britton Founder + CEO, Avvo