I have been working on implementing the Twitter api into a .Net website. After some searching I discovered Twitterizer. It is a .Net dll that you can include in your project. This has made it easy for me to update my status dynamically. The problem I did find was that the URL posted was not being shrunk.
So using tinyurl I was able to include some code to convert the url to a tinyurl and post it. I found this article Shortening URLs Using TinyURL API in .NET and using the code provided I was able to shorten the url for posting.
I am currently demoing this to a client and will keep you updated on my progress.
.Net
twitter, .net