dont make this more difficult than it needs to be. No need to mess with the terminal app or any commandline.

Simply download the ipk file Jason posted.

Connect your pre to your computer, open webOS quickinstall and click the plus button on the right side. Add the ipk file and hit install. (alternately you could just drag the .ipk file into the quickinstall window and hit install)

Disconnect your pre from the computer and open the MyTether app that was added to the launcher. Hit wifi at the bottom if its not already selected and you'll see a toggle at the top that says "wifi tethering " make sure that toggle switch is set to on and it might ask you to enable DHCP, click on yes and you should be good to go. Now on your computer go to the list of available wifi networks and you should see AoNet. Connect to that and you're good to go.