I recently became aware (thanks, @ppadley!) of a pretty awesome little AppleScript that pulls tweets out of your Keynote presentation's Presenters Notes and posts them to your Twitter timeline. Unfortunately, though, the simple way it used to work was broken when Twitter switched to using oAuth instead of 'basic' (username and password) authentication for using its API.
Luckily, the project, Keynote Tweet, was updated and posted to GitHub, and works in tandem with twurl, a simple Ruby-based command-line Twitter client. Here's how you can get these things working for your own presentations: