Questions about TV Tuners and their uses...

I'd like to get a TV tuner and use it for a TiVo kind of TV recorder (maybe transfering to CDs), To take VHS recordings of my kids and put them onto CDs and stuff like that.

1) Can I use the same line to run digital TV to the tuner and the cable modem. Its Cox cable if it makes a difference.

2) Can I play VCDs on my XBox?

If I can't play the VCDs I make on the XBox I might as well not get the Tuner.

Thanks for the help.

im pretty sure Xbox doesnt play VCD's
as far as i know digital tv uses a digital connector, either svideo or composite (i may be wrong)