I guess once they start, they do not stop. Just a few weeks ago we had some people asking if there will be a twitter solution at launch. Well Microsoft announced officially and it seems their will be quite a few to select from.
This new one just posted a few hours ago on 1800PPC, is one of those applications for Twitter you will have to choose from. It is seems to have a very simple nice design to it, and might be something that even beats the Microsoft implementation of Twitter.