Unlock your Blackberry
Just a thumbs up for Unlock App® straight from RIM's AppWorld http://appworld.blackberry.com/webstore/content/29634?lang=en
Easiest, peasiest way to sim-unlock a phone. Though the app is free, you do pay €9.99 for an unlock code, but unlike many online services, this app really does the job, and you don't need to spread your credit card details all over the web. The app connects via BBM and your BlackBerry account is charged.
Considering that a sim-locked prepay Bold 9900 can be had for £350-ish versus a simfree one for £460 and up, a tenner for an unlock code is not bad