I have an Evo 4g. As far as i know, there is currently no root method available. One that was popular was called UnrEVOked.
As far as rooting is concerned, if you are somewhat competent at reading, researching and using a PC it really should NOT be hard. It also depends why you want to root it. If you want to remove the bloatware the provider added(i have Sprint Nascar and Blockbuster....yuk
.) then rooting is what you need. If you want to change the "OS" or get a a newer version of Android without waiting, rooting is what you need. If you want any sort of noticeable difference in performance, a new phone is needed. LOL.
Also USUALLY there is a way to get S-ON in case you ever need to send it in for insurance claim.
http://www.xda-developers.com/ == This site is the one stop, everything you need to know site for smartphone development, tweaking and hacking. Happy rooting :)
Also, there is a CHANCE that you will brick your phone. Every rooting guide will have a disclaimer, but dont let it deter you. Peopl even have developed programs to unbrick some phones. Just make sure you follow ALL the directions. If you arent sure of a step, make an accoutn and post on there. Google is as always one of the best tools you can have when entering unfamiliar territory.
What phone?