I found this freeware very useful small and it is so simple to use and works like a dream download and convert in once fast
Filename: vdownloader.zip
http://www.megaupload.com/?d=LLAFAO3Y
VDownloader description
Download Google, Youtube and Grinvi videos on your computer in avi or mpeg format
VDownloader allows you to download videos from Youtube, Google Video, Metacafe, MySpace, DailyMotion, Pornotube, and many other similar sites, saving them in AVI or MPG format.
Run Vdownloader.exe and copy the url of the video you want to download. Click on Download button...