Over at Android and Me, they just received the HTC Inspire 4G. In the brief description, the reviewer noted, "Fortunately, I’m happy to report that the HTC Inspire 4G is the first phone on AT&T that allows users to install applications from the SD card and other sources." Looks like AT&T is allowing sideloading of apps which is very nice to read!!
Source: Video: Unboxing the HTC Inspire 4G from AT&T – Android and Me
Source: Video: Unboxing the HTC Inspire 4G from AT&T – Android and Me