True - I usually just record the entire screen (which only works on newer versions of Windows in which the desktop itself is hardware accelerated), and then crop the resulting video in VirtualDub. You need quite a bit of disk space for that tho.
Come to think of it, go with Expression Encoder. It's a free download from http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=2721 , and records any region of the screen. It records audio as well, and has some basic features to trim the video as well. From there you can import it to Windows Movie Maker, add title and effects, and post it directly on YouTube. :3