While the iPhone finally supports third generation wireless broadband (assuming your neighborhood is upgraded), it still can't officially be tethered and used as a wireless modem for your laptop. It looks like some innovative folks have crafted a workaround. But it's not exactly a breezy process, requiring you jailbreak the phone, then use 3proxy and MobileTerminal. A tethered iPhone is also apparently quite the battery hog, and AT&T will probably come down hard should they find you're really gobbling up the data (your agreement gives them the right to sock you for consumption exceeding 5GB/month). How To Tether The 3G iPhone - Unofficially, anyway... - dslreports.com That's to much just to get your phone to tether. I really don't mind, but still. It would be cool if they just let you tether, because there's only so much you can do on a phone.
AT&T doesn't explicitly say there's a 5GB limit on iPhone plans. That's a common misconception. So if you use more than 5GB on the iPhone AT&T doesn't have any grounds to come down on you. The 5GB limit only applies to Unlimited Data Connect plans (laptop cards) and Unlimited PDA w/tethering plans.
I have a 3GS 3.1.2 JB iphone. I am wondering if the tether update at help.benm.at will work to enable tethering. Does anyone have the same phone configuration as me and have tethering working. I have not tried it because I know once I do it, it will screw up my WIFI networks, visual VM, etc and would rather not do it unless I am pretty sure it will work. I had it working back on 3.0 but have updated since and wanted to get it working again. Thanks, aje