Direct is completely possible, you need an adapter first of all, I suggest the 1/4 inch guitar jack to RCA Right and Left composite adapter, plug it into the front panel rca input I think it's like input 2, you can even set it so you can here what you are playing through your computer speakers while recording.
What you need ot do is set it so that you are picking up that input, and hearing it through your speakers, then use the creative media player to record select "What U Here" as the input for recoding, select record format and quality. I suggest 160 kp or higher mp3, if you plan to use it for sampling or something that reduces quality a lot either use ultra high mp3 like 360 kbps or even lossless format.
Get the adapterm plug it in, and mess around and you will be good to go in no time. I used to record with my Audigy 2 zs platinum allll the time. It's a great system. Not to mention just using your computer speakers (if they are decent) as an amplification system works great if you need to be quiet or are in a dorm or something,