Nope. From what i've heard there is no tethering capability for the iPhone 2G. I'm sure if you jailbreak it is possible though.
Check out the "Mroogle" link in my signature. It's a search engine created by a former Mod on here that does a thorough search of the MacRumors forums. Some people can be real jerks on here about posting a question that has already been asked, but I know it's difficult to find answers.
Cheers - Eric