Yes apparently it is back, unfortunately (or fortunately, depending on how you look at it) you do have to jailbreak. but you do not have to pay for the app, and there is no extra setup with an adhoc... basically this app is supposed to give back the "stock" iPhone tethering options. and they claim it to be faster than PDAnet. it is an app called "MyWi", here is the link i found to read about it:
http://www.redmondpie.com/enable-tet...rmware-iln456/
Currently i am in the process now of testing this. i have been using 3.0.1 with the old ipcc file 4.0 which allowed me to have MMS and tethering on the day MMS was activated. i am now updating to 3.1.2, and then i will be JBing with blackra1n (which i have also read has been much less laggy than recent other JBs).
here is the blackra1n link:
http://www.iphoneos3.com/?QtTfrgkV
...if this is not allowed please let me know i will remove it immediatly, i dont want to loose this whole post. i feel it is very useful and a lot of people have been waiting...
I will keep you posted on my progress...