SpeedBit Video Downloader it’s a free program for Windows XP / Vista / Server 2003 / 7 and support Internet Explorer from version 6 and later to download videos (Flash file format) from sites like Youtube, Dailymotion, Facebook, Google, etc…
To watch the videos then you need an FLV player like Videolan VLC or FLV Player.
Video Accelerator it’s a free program too from same software house (it exists a Premium version too) that as the name says works as accelerator for the videos watched from Internet (supports over 150 sites). For Windows 2000 and later, and Mac OS X. Supported browser: IE from version 6, Firefox from version 2, Opera, Safari, Maxthon, Netscape, Flock, AOL.
By the way there is also Bywifi a free downloader from many streaming sites, it work also as transcoder of video files and P2P accelerator all in one solution.