O2 has only been operating its Twitter SMS service for two weeks, and has already reached the milestone of a million Tweets having been delivered through the service.

"We've now topped over a million free Twitter SMS messages", O2 told CNET UK, "and that doesn't count the ones people are sending to Twitter either". The service was originally due to be switched on in mid-August, but went live early at the end of July.

If you want to sign up, and you're an O2 customer, then sent an SMS to 86444 to get set up. There's a 600-tweets-per-month fair usage policy, beyond which you'll be asked nicely to ditch the yappers.