In case you didn't see it on Make Blog and you're in the New York City area, I teaching a "connect your Arduino to Twitter" class/workshop on Saturday afternoon.
Full details are at http://www.eventbrite.com/event/351294732
. Students will come home with a LCD/button shield from Nuelectronics and working code to post to Twitter from an Arduino using a standard Ethernet shield, plus knowledge of how it all works. We'll also cover some security issues, how to talk to the LCD and read it's buttons, and have a lot of fun.
After the class, I'll post the presentation and materials online.