For some good reading material browse through the 3 links in my signature.
I went through the steps in the first link to 1) root, 2) install sprecovery, and 3) make a backup. Then I did the steps in link 2 to install that rom that came with wifi tethering. I paid a buck for SetCPU and that was it.
To answer your question, the first link below has a link to get you back to stock, just how your phone is now.