The EVO 4G was rooted a few days back, but Android Central have pieced together a step by step guide on how to do the dirty yourself. This was in large part taken from the xda-developers forums, which is where all the tech stuff has been going down regarding the rooting of the EVO 4G. If you want to get familiar with the source materials, we strongly suggest checking it out yourself. It will really give you a flavor for not only how to root the device, but how these things come to exist. Here is an excerpt from Android Central on the whole process.
1. Download this file (PC36IMG.zip). Move it to the root (as in top level) of the Evo’s storage card.
2. Turn the phone off. Once it is, hold down the volume button and the power button until you get a white screen and some text. You’re now in the bootloader. It should automatically start checking the PC36IMG.zip file you put on the card.
3. Once it’s done, it’ll list all the images on the card and ask if you want to flash. (This is your last chance to back out.) Say yes, and we’re on our way.
4. After it’s done, it’ll ask if you want to reboot. Surely.
For the whole article, click here.