December 24, 2012 7:45 PM EST
My suggestion is to start describing your business model first, e.g. what is your value proposition, customer segments, revenue streams, key resources needed, key partners etc.
You need a business plan (I mean, in classic terms) only when a potential investor or partner has fully understood your business model and wants to go ahead with the project.
A typical business model describes 5-9 "building blocks" of the concept. Search for keywords like business model canvas, business model generation, lean startup
---Business plans adviser