First of I would like to say that none of these hacks and files are my own work. This stuff was done by all the amazing phone developers over at XDA Developers. I am am simply writing a few posts on rooting the HTC Evo since most of the information was all spread out over the forums and I had a hard time gathering it all together in a organized manner.
The WiFi chip in the HTC Evo supports Wireless N technology, which allows for faster throughput on your WiFi connection. To use this you need a Wireless N capable AP or router. For some reason HTC decided to disable the wireless n capability of this chip but this can be fixed. I am going to assume that the reason this was disabled was battery life but I am not really sure to be honest. Anyway the hack used to be more complicated but some of the nice folks over at XDA packages up a zip file which makes this hack a breeze.