Depends on what the exact purpose is. If you are simply in the idea stage, I'd spend time really figuring out if your problem is really a perceived issue with others and if it is big enough for them to pay for it. Getting your first dollar gives you something to scale with and gives you customers to interact with to make something they'd really want to get behind.
If you are doing it for a bank loan, then most templates on Google will give what you are looking for. Here are some templates from Entrepreneur.com: http://www.entrepreneur.com/formnet/businessplantemplates.html