How do I use a SIM-less original iPhone as an iPod Touch?

Hello! I've got a SIM-less 1st gen iPhone with the latest OS that is stuck on the "emergency call" initial screen and that iTunes refuses to deal with. I have a customer who would like to buy it for use as an iPod Touch-equivalent device. This question has been asked before, and I realize that I need to jailbreak/unlock this phone in order to get iTunes to see it without a working SIM, but I've spent 3 hours applying various jailbreak apps with no real success. They all either hang, claim incompatibility with my phone or the OS or whatever variation of the firmware they are attempting to apply, etc. Replies to this question have all been generic "unlock your iPhone" or "jailbreak your iPhone"...is there someone who has actually done this who can provide more specific instructions, i.e. what app, what version, steps involved, etc.? Please note, it's not possible to use the easier jailbreak methods (i.e. jailbreakme.com) with this phone, because it is stuck on the initial screen and therefore needs an external application to do the work.

I wouldn't normally post a question such as this, but considering that original iPhones are increasingly impractical as phones, but are still useful when recycled as iPod-like devices, I think it's an issue that is not going to go away and might as well be solved.

Thanks!

John