http://androidforums.com/ally-all-things-root/263285-guide-froyo-2-2-1-root-users.html

not real easy, but you get to keep root and fastboot. works very well, just follow the steps carefully

 

You need a computer....its telling you you need WIndows....

 

the guide tells you where to put the files...should only be 2 files that go onto your sd card, the rest are on the puter. follow the instructions very carefully, and you should be fine. read, reread, then re-reread. after this, you can download barnacle, pdanet, whatever you were using before to have wireless tether again.

 

If you just want to root for internet there is a program called SuperOneClick 1.6.3 that is a much easier to use at [APP]SuperOneClick v1.6.3 (Root, Unroot, Enable Non-Market App, Get UNLOCK code) - xda-developersMake sure to get version 6.3.1 and follow the instructions on the page exactly, and consider donating to the developer if it helps you.
You can also look through the thread on here about it http://androidforums.com/ally-all-things-root/269555-oneclick-root-ally-2-2-1-froyo-avaiable.html