Are you talking about recording from the FOH console directly so that you can remix afterwards to make a "live cd"?
To do that you will need as many a/d converters as channels you will want during the recording. You could buy a MOTU Multitrack recording setup and the associated software to run it, but Its highly unlikely that a laptop will be able to do this. It would take a pretty fast computer with a high degree of reliability. Were talking about 1.5 Mhz or faster motherboard, IDE 80 gig hardrive running around 7400 rpm or faster and 512mb of ram on the PC side. The MOTU 2408 will cost you nearly $900 per 8 channels of inputs, this is on the cheap side mind you. The MOTU I believe comes with software for driving it, there are other systems out there but it won't be as integrated. a Digi001 or 002 will do only 8 channels max at a time, but the 001 is $800 and the 002 is $2000. You could buy a HD24 hardisk recorder or Mackie equivalent and it would probably be the best way IMO, just run the buss outputs into it or the direct outs depending on the FOH back panel. How new are you to recording?
SoMm