Unrevoked 3 is a program used to "flash" your cell phone. This is the process of opening up your phone so that it can be used with other carriers aside from the one to which you are currently set. Unrevoked 3 is now available for various smart phones, including the HTC Evo. In fact, you can find the download for free online.
Tap the "Internet" icon on the touch screen of your Evo to bring up the browser. Navigate to the Unrevoked 3 site for the Evo.
Click the "Download" tab next to your particular model Evo and the program will download to the handset.
Tap the "Unrevoked 3" icon on your Evo and the program will open. Tap the "Run" tab on screen. The system will run and your phone will be flashed.