FIRST OFF WELCOME TO THE FORUMS!!!!!!!!!!!!!!!!
so to follow xtreme and lesawag
since you are rooted you can back your apps up with titanium backup. and make sure that your contacts are linked to google and not your phone. otherwise you will loose your apps and contacts.
i would also download vr superwipe as well:
MEGAUPLOAD - The leading online storage and file delivery service more on this later
1.download both files
2.transfer the files to your sd card
3.go to recovery (power off then press and hold power+vol down and select recovery)
4.select "backup and restore" and select"backup" to make a nandroid backup
5.next wipe cache partitions, data/factory reset, and in "advanced" wipe dalvik cache
6.slect "install .zip from sdcard"
7.find and select vr superwipe. this will super wipe your phone. you need a really clean environment for your new rom to be installed
8.then again select "install .zip from sdcard"
9.find and select your rom file
10. it should do its thing and then select reboot
now the first reboot will take longer then usuall. this is normal as your phone needs to build dalvik cache up.
I would definitely recommend what lesawag said and read the
http://androidforums.com/evo-4g-all-things-root/194918-rooting-dummies.html guide. in the after rooting section.
hope that helps.