Then don't rip him off. Cut him a deal of 10% of "the company" for doing nothing - just for his idea. Explain how this will be worth hundreds of thousands of dollars if the idea actually matures... and that you wont be making anywhere near 95% of the rest of the money since you will probably have investors/other costs to think about.
Right.
I'll basically be doing everything. I know ideas are a dime a dozen. Even if he wanted to help with programming or promotion or whatever he wouldn't know how.
I'm planning on putting up my own cash and doing all of the work on it.
But, it was his idea.
So, I guess my question would be what's the idea worth? The dude is my friend, I don't want to rip him off.