This is an ongoing list of things I run across that might be of some use to entrepreneurs and students developing business ideas. It will change regularly, probably by appending new information for a while, then, once there is enough to bother with I might organize it.
business.valuations.com – This site, with very few inputs (you do have to join it though) will give you a rough valuation of your business. It’s based on revenue, so it could be less useful to nascent firms.
custompartnet.com/estimate/ – This site has several estimators to help you determine how much it would be to manufacture various products and parts. They also have a sections on rapid prototyping, manufacturers, materials, and lots of other really useful and interesting stuff.