The 503G is a WM6 Standard device running on GSM with UMTS/HSDPA, a 520MHz processor (nice!), 256MB ROM, 64MB RAM, WiFi, and a QVGA screen. It’s also pretty thin at 15.7mm versus the BlackJack at about 12mm. It will be available in June for about $750. Click here to preorder or for more info.