[fishfreek]

The easiest thing to do would be to have a video capture card in the PC. Since most cameras output in raw composite video you can then just run the camera right into the computers video capture video input.

One thing to note is that when it comes to enhancing the video after its been recorded you would think that having it digital to start with would be a benifit but in fact its not since you cant record the video on your PC with out compressing it to some degree. (Well unless you had like a 200GB disk dedicated to just the video capture data). That compression causes the enough data to be lost that digitally enhancing the video (ie blowing up someones face) is almost impossible to get anything of any clarity.

If you have multiple cameras then you can get a hardware video switcher to run your camera inputs into and then run the switcher output into your capture card.

Any capture card you get should come with a video capture interface.