I am using this document to expand upon what I wrote in the project description concerning the financial calculations for the information-based product project. Please also see a basic overview of how to write a business plan which has been graciously provided by Professors Romanelli and McAllister . There are entire courses on entrepreneurship and this is not one of them. Therefore I do not expect you to spend a huge amount of time researching every number. However, you should be able to justify every number of your spreadsheet with some logic or some evidence.
Costs are relatively easy to find out.
It's not too hard to find out how much a powerful server costs, how much an ISDN phone line costs, how much you might have to spend on consultants to create your web pages or how much it would cost you to do it yourself, etc. etc. If you are using America Online, for example, you have to have a basic idea of how much they charge for you to be there. It is not necessary to shop around and come up with the best bid for whatever you want, but you should get some ballpark figures. Estimating revenues is harder, so here the emphasis should be on the logic of how you reach your conclusions and on full disclosure of any and all assumptions you make. The more uncertainty that you have about certain numbers, the riskier your project is.