I have an EyeTV 200 - that connects via firewire and works great - I was using it to allow an old iMac G4 to function as a TV (cable box was connected through the EyeTV and the software then displayed the cable picture on the screen).
Difficult to get hold of that particular model, but one of their newer models should work out quite well for you. Try this one...
http://www.elgato.com/elgato/int/mai...oduct1.en.html
Would have to run S-Video or Composite (phono) cables from the V+ to the EyeTV, so will depend on which V+ box you have - not sure if V+ boxes support S-Video but they will do Composite so you might also need a SCART to Composite adapter.