Buying Blackberry 9300

Don't know much about setting up or networks on Blackberrys but I'd like it to be able to use BBM & to either be on O2 or Unlocked (if possible so I can use my own SIM card, wouldn't hurt to get a new number though if the price was right)

I live in the UK.

Anything else just ask.

Skype: Runkkupeppu

EDIT: forgot to add, would rather do the deal via eBay if possible & no time wasters or weirdos thanks