Learned about this today. Have to check it out.
Themattinator - Managing Multiple Twitter Accounts | Performancing.com: "The Mattinator is a nifty little web service which gives Twitter users a way to manage multiple twitter accounts. Unlike using Twitter directly where you would normally have to log in to each account separately to post a message, this web service gives you the interface to choose which Twitter account the message will be posted from.
The design of the website is pretty interesting in and of itself. It looks like something out of a cartoon dealing with spaceships and aliens. However, they have at least made the aliens highlight specific areas of the site and some of them are even helpful. Just don't tick that monster off with three heads and razor sharp teeth."