Does 501c3 require the board to be of a certain size and structure? Does it require that receipts be given for all donations?

The article of incorporation for your 501(c)(3) will have to spell out certain aspects of the board structure in order to be registered in your state, but not in great detail. You shoud be able to find details of what's required on line for your particular state.

Receipts for donations are required for gifts of $250 or greater, but it's good practice to provide them for smaller gifts as well since your donors will need receipts to deduct their donations from their income taxes. Here's some info on what should be included on the receipt: What should be included on a charitable donation receipt? (http://www.boardsource.org/Knowledge.asp?ID=3.135)