I just found out that AT&T and Samsung have released a ROM update for the Blackjack. Here's the full story:
http://www.brighthand.com/default.asp?newsID=12904

The changes are mostly cosmetic (new AT&T logo splash screens), but supposedly this ROM also improves international roaming. Here's the link to the upgrade from Samsung's site. Note: disable popup blocker and then click the "Software" link. Beware that flashing your phone removes all installed software, contacts, etc.

http://www.samsung.com/Products/MobilePhon..._I607ZKACIN.asp

Earl