Video Capture Cards

Video capture cards, or TV cards, are designed to be installed into PCI slots, PCI express slots, AGP slots, or USB. The internet is the most popular use for streaming video. Surveillance is another popular application. the analog signals can be converted to digital signals and stored with on a hard disk drive, CD, DVD, or other storage device.
Performance of video capture cards can be adversely affected by which type of mother board and CPU you're using. Care should be taken in selecting a card suited for your particular system.
Video editing can be accomplished with these cards and software designed to allow the rendering of the video. this also includes audio dubbing and some cards have more than one audio channel for more sound options.
For the laptops, these are USB, Firewire, and PC interface cards that can be used. They have the same functions but are designed more for portable systems. Some camcorders can actually output the video to the computer in digital format with some editing function built in.
I have dabbled in the video capture game only briefly but with good results. I have a Plextor USB digital video converter installed on my XP Home system. I've copied old home movies from VHS onto DVD and saved many hours of video that is quietly disintegrating in the box. There's limited sound on some of the tapes and the quality is awful. I've been able to clean up some of it as well as cut some useless video that might have been taken by the kids. Several minutes of feet and sky.
The Plextor unit does have some really bad limitations though. It apparently does not play well with Windows Vista. If you're going to invest in video capture and editing equipment, you should ask around to see what problems other people have had. You could spend a lot of money buying devices that say they work across all platforms but really don't.