Here's a link to yet another screencasting tool. This one is described as "an extraordinary app with extraordinary speed" Why? How?
"Simply press the ScreenSnapr Hotkey (Ctrl + 1), and almost instantly have access to a URL to share on IM, Twitter, Email, or any other virtual medium. So go ahead, take a Screenshot. It's a Snap!"
Here's a brief video introduction.
You can download ScreenSnapr for Windows XP or Vista.
[And here you will find a list of over 70 screen capture and screencasting tools]