With TeleTwitter you can update your Twitter and also follow what your friends have written on theirs right from the Windows desktop. This simple tool, which is based on the Adobe AIR platform, features a sleek interface where you can see a list with all the messages that your contacts have recently added to their Twitters. There's also a basic text field from which you can send messages to your own Twitter, but unfortunately you won't be able to read them. Also, I noticed a couple of bugs: first, if you enter a wrong password, the program freezes; second, if you hide the menu bar, there's no way to bring it back (or at least I couldn't find it).
TeleTwitter works fine if all you want to do is follow what your friends are up to, as the program updates the Twitter timeline automatically and enables you to keep up to date.
However, if you'd like extended functionality such as the ability to also read your own tweets or manage several accounts, I'd recommend other desktop clients like TwitBox or Twhirl, which is also based on AIR.
TeleTwitter is a simple desktop Twitter client that enables you to follow your friends' updates, but lacks extra features you find in other similar tools.