For those of you lucky enough to get to Macworld this January, IDG has recently released its own iPhone app, iMacworld. Currently it has details of show exhibitors but IDG is promising further updates. I assume that will include maps, conference schedules, and related useful information.
Now I'm going to cross my fingers that AT&T has adequate Edge and 3G coverage. Last year it was insufficient and the iPhone was of little use with no signal.