Yes there have been three limited solutions to tether, one that was on-off-on-off again in the AppStore and two (iPhoneModem) in Cydia. All three only did socks proxy so it was pretty much limited to web browsing. Since PdaNet popped up in Cydia, I send a story hint to ( GIZMODO, ENGADGET, TUAW ) and none of them have picked this up. It surprising that the limited tethering solutions generated all the buzz months ago but this %100 WI-FI router solution on the iPhone can't see the light of day.
Most of the news seems happy to keep on the good graces of Apple and not highlight 3rd party apps unless they are useless toys.
I'm scratching my head on this one.
I tried PdaNet as soon as I saw it posted. It worked well and will definitely help out in a pinch.
You can find it here
PdaNet -- Use your iPhone as a Wireless Router for your PC/Mac