Skimmer was just released today and I'm impressed. It's a really slick and visually appealing Air application that makes updating multiple social networks a breeze.
"Skimmer℠ is an Adobe AIR desktop application designed to streamline, beautify, and enhance the experience of participating in your most frequently used social networking activities. It improves upon day-to-day interaction with multiple social networks, removing distractions and providing a rich content experience from Facebook, Twitter, Flickr, Blogger and YouTube. Skimmer’s spare, modern aesthetic sets it apart, creating a welcome, handsome social networking hub on your desktop that is particularly suited to multimedia content."