You have to unlock the phone first.
Check out this thread.
http://forum.ppcgeeks.com/showthread.php?t=33857
Dcd's roms are great as well as no2chems. Its really a personally preference which people use. If you are new to flashing etc. I would recommend using the ppckitchen for its ease of use. And since your on verizon its a little less involved.
But the most important thing that you could know is DONT let the sprint customizations run.