From the If-You’re-Really-Desperate Department: some advice.
If you’re giving a presentation, make sure your script is full of tweetable content. Think in terms of 140 characters or less. As you’re preparing, literally write out those tweetable points to ensure they’ll fit with room for retweets to spare (right around 100 characters is about right).
If your goal is to share your story not just to those in the room, but their followers as well, this will ensure you’re getting maximum pass-along for yourself and your message.