Judy: my cell phone number stays the same- I had it transferred to the new phone.
As for the twittering… I’m following tweets from folks like John Cleese and Adam Savage (from Mythbusters). And I’m posting a few twitters each day about what I’m doing or things I’ve found that are interesting. Is Twitter worthwhile? Hard to say, but it is an interesting diversion.
As for using it: go to http://twitter.com, sign up for an account, and type something in the little box. Then use the search function to find some people you want to follow. That’s pretty much it 😉