Microsoft is prepping for the second wave of Windows Phone handsets – and so are U.S. carriers.  AT&T is among the first to show off Windows Phone 7.5 phones, including the HTC Titan and Samsung Focus S.

Neither of the phones have been given pricing or release date details – at least not publically – but we know a great deal about each of them aside from these admittedly important details.  Each features a fast processor, a large screen, and the latest version of the Windows Phone OS, in addition to the usual array of wireless tech.  Both are also HSPA+ ready, too, so you’ll get faster download speeds than standard 3G models.

One interesting detail: the Samsung Focus S, like its predecessor, will include a microSDHC memory card slot for additional storage.  Microsoft’s other smartphone offerings, like Apple’s, lack memory expansion.  Here’s hoping they’ve solved some of the issues that have plagued the 2010 Samsung Focus.