okay I have the following-

an ibanez soundgear 4-string bass (passive)
a hartke bass attack DI/preamp
a 10-watt bass amp
this computer, which has some kind of soundcard surely

how do I record stuff? =( where do I begin? I just want a sound that's clear enough to be heard as an mp3 over the computer, like on youtube videos such as

http://www.youtube.com/watch?v=bX9C96zwYfQ

The easiest, most cost effective thing for you to do right now is to go to Radio Shack and purchase a cable with 1/4" plug on one end and an 1/8" plug on the other. This will allow you to plug directly into your computer. From that point you'll need something to record with. The easiest thing to do here is just search (here or google) for a free recording program.

Good luck!

http://audacity.sourceforge.net/

Audacity works for me. It is free and simple to use. I have tried to plug into my sound card from my bass and it didn't work very well for me. I use the headphone out on my practice amp and plug into my sound cards line in. I can control the strength of my signal better that way.