There are ways to do this, but the easiest is to use an Alesis Masterlink. It isn't really direct to CD (you record to the internal HD first), but all you have to do when you're done recording is pop a CD-R in and push the "Create CD" button.
Plug your laptop right into the mixing board and record right to Cakewalk or something. Burn a CD right off of those WAV files. I used to do that all the time before I got my Roland 2480.
You can do it with a standalone CD recorder. The Alesis Masterlink (mentioned above) is a particularly snazzy standalone hard disc/CD recorder that records at high-resolution as well as standard. Less snazzy machines like the Philips boxes, will work too.
You can also use a separate converter with either setup. The theory of these is that they do a higher-quality conversion than what's built into a soundcard or typical standalone. Sort of like using an outboard mic preamp with a mixer.
Which leads to the observation that the more tricky thing about recording a band live to two-track is micing and mixing.