KeepTube is a software that downloads and plays videos/audio from almost any web site like :
YouTube, MySpace, Yahoo, MSN, AOL, IMeem...It downloads FLV,MP3,MP4,WMA,WMV
It supports HTTP/RTMP/RTMPT

Feature
* Download almost any web sites
* Download FLV,MP3,MP4,WMA,WMV
* Download multiple videos concurrently.
* Play video while downloading videos.
* Create and edit your favourite play list.
* Loop play your favourite list.

The license of this software is Freeware, you can free download and free use this video downloader software.