An iPhone app would be great. Especially if it could read tweets from your followers between songs, though I'm not sure if Apple gives you enough control over the iPod to do that.
That would be a fun idea. I'd probably buy it right away and start using it more then Tweetie (leave it open in the background while doing other work and just passively hear tweets).
Incase anyone does want to do this, Apple doesn't directly tell you when a song is starting/stopping, but they do tell you how long the song is (with MPMediaItem and the key MPMediaItemPropertyPlaybackDuration) and how far into the song you are (with MPMusicPlayerController).
To add why, it's rare that I'd want to listen to something when it's quicker for me to scan. The only time I'd do that is if it's inconvenient for me to read, ie when I'm on the move or driving. Then, I'd like for it to be fed to me audibly.
Good job getting it up and running. What do you use for text to speech conversion?
Incase anyone does want to do this, Apple doesn't directly tell you when a song is starting/stopping, but they do tell you how long the song is (with MPMediaItem and the key MPMediaItemPropertyPlaybackDuration) and how far into the song you are (with MPMusicPlayerController).