I stand corrected about the mixer!
Its, here how I have mine hooked up - keep in mind this is not my #1 recording rig, it sits by my general purpose computer that I use for almost everything, including recording from Radio & cassette.
Mixer outputs: The mains go to the sound card inputs. The Control room out goes to an amp that feeds some Yamaha monitor speakers. The tape outs & aux (effects) outs are unused.
Inputs: Channel 1 & 2 -- I have a Stereo receiver which brings in playback from radio, cassette, and turntable from its "tape outs"
Channel 3 & 4 - a return from the output of the sound card. 5 & 6 - A seperate audio output from an ATI All-In-Wonder card (lets me watch TV on the computer)
Mr. Bane is right about being carefull to avoid a feedback loop. When recording or monitoring the input of the sound card the playback needs to be muted, either via the volumne applet in Windows or by turning the playeback volumne off at the mixer. Whe I used to have a Creative Audigy card this was a constant problem, because this card always defaults to passing any input through to the outputs. Since switching to the Audiophile 2496 this is a non-issue, because of the very nice mixer aplet that comes with this card. You can set up mixer "presets" - I have one with the cards line-in muted, and one with the playback muted (I can still monitor inputs from the mixer). So I just click once with a mouse and feedback isn't a problem.