My Arduino Twitter alarm was working fine. I updated with NeoCat's Twitter library 1.1.0 incorporating Oauth as required by Twitter, but I can't get it to work.
You need to register at http://arduino-tweet.appspot.com/
The arduino can't handle oauth*, so you register at that website and it acts as a go-between between your arduino and Twitter, handling the oauth stuff on your behalf.
*probably. There may be a way to do it, but I haven't seen it done