Most soundcard inputs on normal PCs are like a little headphone socket (like on a walkman) so you need a dual phono to mini headphone jack cable, then you just need a wave editor to record it with once you got that plugged in.
Then you save the recording as a wave, or chop it into individual tracks before burning to a CD
most soundcard inputs on PC's are also shit quality - so if you dont want your mix sounding like the pull string on some cheap plastic toy - you'll wanna get yourself some professional quality inputs.
I reccomend one thing to everyone who asks this question - the Edirol UA-1A.. it will plug straight into your USB port and provide you with good quality inputs, and it also uses standard RCA jacks so you wont have to worry about finding a Y cable.
As for recording software... there are various free options you can download, probably the best of which is Goldwave.
I have an M-audio Revolution 7.1, so the recording quality on my card is excellent (uses the same chip as the M-Audio Audiophile 24/96).
What I did, from my DJM-600, is ran a single RCA cable (the DJM-600 has Rec. Out ports which are RCA), to a Y splitter (the splitter should be female RCA -> male headphone), and plugged in to the INPUT port on my soundcard, NOT the Mic port (you will get crappy quality if you use the mic port).
Hope this helps.
Oh, one more tip. If your mixes are coming out REALLY distorted, try two things:
Lower the Master Attuniation on the back of your mixer (its labeled as Master Att. on my 600, not sure about other mixers)
If that doesn't help, lower the Line In volume in Windows to a more acceptable volume. That should fix the distorted sound.
Software wise, I use CoolEdit Pro myself, it allows you to place CD track markers, edit the wav, all kinds of things.
cant u chuick it into the line-in?
i got mine going into my stereo, which has a headphone jack, which i plug into the line-in of my computer..
the only problem I have is that my computer is shite, and whenever i try and save my mixes my computer crashes