Also, understand that you're going to need both regular bookkeeping and professional (CPA and so on) accounting advice on taxation. If you want to jump ahead on things, start looking for these services. Interview people, and ask people who they recommend.
If you're not sure, still considering, still working on your business plan, then your time and effort is better spent on the planning than on this red tape detail.
Tim Berry is the chairman of Eugene, Ore.-Palo Alto Software, which produces business-planning software. He founded Bplans.com and wrote The Plan-As-You-Go Business Plan, published by Entrepreneur Press. Berry is also a co-founder of HavePresence.com, a leader in a local angel-investment group and a judge of international business-plan competitions.