What do you think would be an appropriate billing rate?

Here’s the situation. I have a former co-worker whom I also consider somewhat of a friend. We worked together for this company for about 2 1/2 years and the company went belly up. He had been working on starting his own companies and now that he’s out of work, he’s managed to really get the companies off the ground. He is an IS guy, I’m a numbers guy, and whereas he can develop websites and run the business, he doesn’t have the proper administrative grounding to get the thing going. Basically what he needs right now is to have me come help him set up some companies in Quickbooks, set up the charts of accounts and get his backlog of data entered in so that he can produce financial statements that his tax accountant can use to file his returns. Then of course to train him how to enter transactions on an ongoing basis and to potentially consult here and there as he has a question going forward.

I’d love to take him up on it, I’m unemployed, I’m capable of doing the job and I’d love to help him out as a friend. But he’s basically asked me to name my billing rate, and I have no idea what it should be. The rate should take into consideration that a) any hours I spend doing this I can’t spend looking for work, b) I will be responsible for all self employment taxes, and c) any income reported will have to be offset against my unemployment benefits. Primarily, I’d like to make as much as I can to the extent that it’s fair, my family can really use the money, so the more I make, the longer I can ride out this economic downturn. But, I want it to be fair to my friend as well. I’m not looking to say that because I know he’s motivated to pay me whatever I think I’m worth and what will motivate me to do the job so that he can get his taxes filed and keep up with the growth of his company, that I’ve got him over a barrel and should ask for top dollar. He trusts me and I don’t want to take advantage of that, and I’d sincerely like to help him out too and leave a good taste in his mouth over the whole thing, because in the future he could be a good reference for me, he can help me with computer issues, and maybe someday he’d be able to hire me full time, plus he’s a good guy and my wife and I get along with him and his wife, so I just want to do the right thing. So, I don’t want to ask for a number that is arbitrarily too high, but I don’t want to ask for far less than would be fair just because I don’t know what I’m doing.

Any thoughts on what would be an appropriate rate, or any sources I can use to develop one. Since I’m not a CPA or a professional services contractor, I’m not looking to charge what they would charge (sometimes upwards of a couple hundred bucks an hour), but I don’t want to end up working at something that doesn’t ultimately get me employed full time again, and have essentially no extra money (or less than I was making on unemployment) coming in after I take care of all my self-employment tax issues. Thoughts?