“Q: Q. Is it possible to plug in a TV cable to my computer and use it like a VCR to record programs?
A: A. In most cases, you just need a TV tuner card for the computer and a program to do the recording…
…Some cards include their own recording software, but programs like SnapStream’s Beyond TV (www.snapstream.com) give TiVo-like powers to your Windows PC. You can also buy the Beyond TV software bundled with a compatible TV tuner card if you haven’t made the hardware purchase yet.“
NY Times Technology Q & A section (silly mandatory registration required: use bugmenot.com to bypass)