Honorable Mention: Find And Call
We didn't want malware authors to have to write something particularly sinister just to crack a top 10 list. (They care about these things, don't they?) So we're giving a shout-out to Find and Call, which presented itself as a phone book application -- and kinda was -- except that this one also carried a piece of malware that would upload contacts to its friends in the spam community who would then try to propagate the app in the apparent hope of building the most fantabulous text spam list, ever. This is believed to be the first time that Apple needed to deal with malware that slipped past the much-vaunted cyber-goalie in front of its App Store.