Samsung has released a Windows Mobile 6.1 upgrade for the the Sprint Ace (SPH-i325). If you have a Blackjack Ace, you can get started on your upgrade here . Not only do you get all the 6.1 goodness, Sprint is enabling turn-by-turn GPS navigation, so get yours today!
If you're sporting a Samsung BlackJack II, you can now upgrade to Windows Mobile 6.1 by going here .