Are you crying in your pint because you want a Blackjack but don't use Cingular? Well then cry no more, because GSMPhoneSource.com is now able to SIM unlock the Blackjack for use on any GSM network!!
The price is US$34.99...so logon to ebay and buy your Blackjack! Then click on over to GSMPhoneSource.com for some unlocking fun. CLICK HERE FOR DETAILS
EDIT: Confirmation of the service working can be found here in this HF thread.