Nothing's certain yet, but rumor has it the BlackJack won't be getting a Windows Mobile 6 update until some time after June. AT&T users were probably counting on somewhat of an earlier update, seeing as T-Mobile's Dash already got theirs last week, but no such luck (supposedly) for now. Of course, this is from unofficial sources, so you may have better luck once AT&T actually makes an announcement for real.

BlackJack WM6 Update: Q3 at best [WMExperts via Boy Genius Report]