Then it's about getting a group of advisors and professionals to look over your plan. Then and only then are you ready to go looking for money. Too often people go see the "people with money" before they are ready and wonder why they are not taken seriously. It's only after you have put in serious effort that people will take your idea seriously.
A great book on this subject is by Keith Cunningham, called Keys to the Vault.
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.