I'm the worst person to help you. I've only wiped a blackberry once, and it was a piece of cake. If you hit a snag, someone will help.
You can check with your carrier to see if they have the OS, or see this post:
http://www.blackberryforums.com/rim-...tml#post782711.
You can use any carrier's OS so long as it is for your model blackberry. Follow the instructions in the faq.