Choqok is a micro-blogging client for KDE4. It supports Twitter, as you'd expect, and Identi.ca. It also works with Laconica services running on local networks. The name comes from the ancient Persian word for sparrow, sparrows do tweet but not in the way Choqok does, unless things were different in ancient Persia. this version, 0.9.55, is the first beta for the upcoming 1.0 release and is already very stable.
Choqok uses a tabbed interface, at the top are tabs for each of the services you use (you won't see these if you only use Twitter) then each service has tabs to show the main timeline, replies, and your inbox and outbox for private messages. Choqok handles the various support services that have grown up around Twitter, such as TwitPic and multiple URL shorteners. A nice feature is that when you hover the mouse over a shortened URL, it looks up the actual URL and display it in a tooltip.
When the window is closed, the system tray icon shows the number of new tweets since you last looked. Choqok can also use the KDE system notification feature to show new posts, although this can be quite overwhelming if you follow a lot of people (or a few verbose ones). Right-clicking the system tray icon lets you make a quick post without the need for the main window.