Root and then WiFi Tether

[Robfactory]

Unrevoked did an easy root app click here to download.
Just install and run.
Reboot and that's it.
And once you root you can run WiFi Tether and avoid the $30 charge.
Click here to download WiFi Tether.

 

[Aragorn]

Dude, there's an entire forum dedicated to rooting and the things you can do with it.
All Things Root (EVO 4G) - Android Forums