This is template for Alex Osterwilder's Business Model Canvas
http://www.businessmodelgeneration.com/canvas
it is a tool for quick and fairly easy clarification of business models.
Original canvas is good for showing and analyzing existing businesses, however for startups, I found Ash Maurya's one, a little bit more convenient: http://www.ashmaurya.com/2010/08/businessmodelcanvas/
Idea is that you will fork this, use it to analyze your ideas. Make versions old fashion way, by copying so you can display your idea evolution more easily.
I provided two alternative templates, layouts: canvas.html and startup.html
I have to mention existing online tools as well, however I do believe this and paper to be superior.
Here is one from Ash Maurya's Spark59: http://leancanvas.com/
And there is one promoted by Steve Blank: https://www.leanlaunchlab.com/
Zeljko Dakic