Looks like someone figured out a way to tether.
http://forums.precentral.net/web-os-...-around-2.html
Prerequisites:
A rooted Pre, with ssh installed
An SSH client for your computer (Linux: ssh, Windows: PuTTY)
Linux users only: Root access, the bnep kernel module and the following commands: pand, rfcomm, hciconfig, hcitool, ifconfig
Walk-though:
Open bluetooth preferences on your Pre. Turn on bluetooth and wait until it says your phone is discoverable
On Windows:
Pair with your Pre (right click the bluetooth tray icon and select add device).
Right-clicking the bluetooth tray icon and selecting join a bluetooth PAN will bring up a dialog to join a network.
Select your pre and connect.
On Linux:
Start bluetooth, run '/etc/init.d/bluetooth restart'
Run 'hciconfig' to get the name of your BT adapter. Its probably called hci0 but if not, replace hci0 with this name from now on.
Run 'hciconfig hci0 up'
Run 'hcitool scan' to look for devices. Select your device and copy the address (something like XX:XX:XX:XX:XX:XX)
This step shouldn't be necessary, but it was for me: Run 'rfcomm connect hci0 XX:XX:XX:XX:XX:XX 1'. If you were successful, there should be a phone icon next to your computer's name on your Pre.
Open another terminal. Run 'pand -n -c XX:XX:XX:XX:XX:XX', there should now be a globe icon on your Pre. It should say something like bnep0 connected, remember this name, use it in place of bnep0 in commands from now on
Run 'ifconfig bnep0 10.1.1.11 up'. Test the connection by running 'ping -c 4 10.1.1.10' If you dont see errors you're connected.
SSH Users: Run 'ssh -D 8080 -p 222 preuser@10.1.1.10', where preuser is your user name on your phone.
PuTTY Users: Enter 10.1.1.10 in the host name blank, and 222 in port. Go to Connection > SSH > Tunnels, enter 8080 in source port and select 'Dynamic' below. Click add. Click open, and login to your Pre.
Here you have two options to configure network access:
Per Application: Configure whatever application you use to use the SOCKS proxy at localhost:8080. For example to configure firefox, go to Options > Advanced > Network > Connection Settings, select Manual proxy, and enter localhost and 8080 in SOCKS Host and Port
Generic: Look at tsocks (for linux) and FreeCap (for windows). I haven't used them, but they should allow any application to use the proxy
I'm pretty sure that credit for this goes to fish199902 at precentral.net
In case anyone else wants to do this here are the links to instructions on how to root the pre and install SSH on the pre:
How to root the pre:
http://predev.wikidot.com/rooting
How to install SSH:
http://predev.wikidot.com/adding-the-ipkg-repository
This probably seems like a lot of work, but at least it shows that a method has been found. I'm sure it's only a short matter of time before someone develops an app that will do this automatically.