It might not be much help but Tweet a Sound posts text to Twitter, have a look into the guts to see what's going on, I think it uses [ajm.ruby] from the AJM objects collection. Good luck investigating!
Any updates on this? I've downloaded Tweet A Sound successfully, but as it's a standalone app, I can't open it up to see what's going on inside ... can I? Also, I'm having a bear of a time with ajm.ruby. It seems to be outdated. So any direction I can also get on this exact same question would be amazing.
i am afraid that you would have to do this in java using [mxj] and the twitter api. i haven't found a good external for that so far (i seem to remember that someone did this a while ago, but not if it supported pics). seach the java forum for twitter.
If you want to see the code mentioned by Luke, you can find it on my blog: http://www.soundplusdesign.com/?p=4213 It's a little out of date though. Some people have been having issues, I think Twitter has changed stuff on their side, although I'm getting it to work on my side. I'm sorry I don't have time to update it properly, but in the meantime it should give you a basic idea of how it works.