AT&T and Samsung have taken the concept of "big phone" to the next level with today's launch of the Infuse 4G. First seen at CES sporting a massive 4.5" display, the Infuse 4G toes the line between smartphone and tablet. PR materials are referring to Infuse as having the largest screen in AT&T's smartphone lineup, though the carrier did at one time stock the Dell Streak and its 5" screen. No matter, though, with its 1.2GHz processor, super-thin design, dual cameras, and Super AMOLED Plus display with Gorilla Glass, Samsung's Infuse 4G now sits atop AT&T's Android phone lineup along with the Motorola Atrix.