he's right: you have to buy a device that comes into 2 flavors: internal and external.
I have one I use with my laptop. I can watch tv and do video acquisition as well.
but I must say that the video rendering is pretty good when watching TV. when it comes to recording a source (tv, video...) the quality drop a bit
dont expect a dv quality out of a video cassette anyway
the connexion is pretty straightforward (if you know how to plug a VCR to a tv you can set up this video recorder/viewers easily). using the software to do the video acquisition can sometimes be a daunting task (depending on the soft shipped with the product)
I have a product from this brand:
http://www.aver.com/multimedia.html
pretty good value for quality
hope it was helpful to you!