Former O'Reilly web producer Justin Watt just made a surprisingly cool video by combining still photos with a soundtrack made in Looptastic, a $5 iPhone app. (There are also free and 99-cent versions.)
Justin used FFmpeg (also free) to sequence the still images, overlay the soundtrack, and render the movie. Click the image below to watch the video and learn how he did it.
His earlier post on embedding videos with JW FLV Media Player is also clever — though, as I discovered, the technique doesn't work on the iPhone browser.
For those with QuickTime Pro, here's the technique I use to make time-lapse movies with soundtracks.