Thanks to Miami for letting me know about this:

Tether Turns One Year Old!
Well if you came for the BB world to Android. You may know this program. Thether has turned one year old today and with that has released it's first Android beta.With the speeds being reported here. I am sure you guys will want to take a look at this one for yourself!

Here's the official notes I recieved about 10 minutes ago.

Tonight we are excited to launch our first Android Beta, just intime for our 1 year birthday. If you haven't heard today marks our first year in business and to celebrate we're giving away six smartphones. You can read more about that here: Tether Turns One Year Old! | Tether
It's been a long wait, but this Android tethering solution is unbelievable. Our lead engineer on this project has seen speeds up to 6.8 Mbps. That's almost 3x faster then our BlackBerry version.
The download instructions are found below. It's very important to follow the instructions carefully. Please remember, this is our first beta so it's not perfect. If you have problems let us know.
1. On phone go to Settings->Applications->Development and check USB debugging.
2. Connect phone to PC with USB cable.
3. If you have a Samsung Android you need to download and install Samsung USB drivers from: (You may need to reboot)
4. If you already have Tether/TetherBerry installed on your machine uninstall it.
5. Download and install Tether from:
(If asked to reboot, wait until the installer is fully finished)
6. Disable your wireless adapter through the control panel network connections panel (ncpa.cpl in Windows Vista or Windows 7)
7. Start Tether on the PC and select Android USB for the connection method.
8. Start Tether on the Android.
Once connected your PC should be able to browse the internet.
If at any point you need to install Tether on the Android again, there is a shortcut in the start menu portion of the Tether group which allows you to do this.

Thanks to gixxerjoe for the excellent tip!