You don't have to send the BlackBerry anywhere, you just give them a bit of info like the IMEI and carrier and they send you back a code. From there, follow the many directions posted here to unlock it.
Posted from my CrackBerry at wapforums.crackberry.com
or just call the carrier. If its your phone, att / cingular / tmobile will give it to you for $0.00 !
Just the wait time can sux sometimes. (24-47 hrs via email )