Music Marketing Author and Course Instructor
Music Ally has posted their thoughts on the best online promotions from October 2008. I was familiar with many of these (the AC/DC video in Excel being my favorite), but there's some other really creative ideas in here worth looking into. Great iPhone app ideas from Snow Patrol, NIN and Pink, and a cool online distribution idea from Ben Folds that leverages iTunes and his live music.
Also: if you are not part of the Twitter train yet, I suggest you give it a look. Microblogging is another great marketing tool that should be considered as part of your overall community-building plan. Even Britney Spears is on board!