After lots and lots of discussion about the iPhone getting some push technology and the ability to run applications in the background, there was some rumor that a 2.2.1 (or a 2.3 or 3.0) might ship in Q1 that would carry this functionality.  Unfortunately, Apple seems to disappoint developers once again by throwing out a minor patch update of 2.2.1 instead.  The patch doesn’t address much unless you are an iTouch user with DRM’ed music.