My battery light goes on when the car is off, and goes off when the car is on. I was told to pull the fuses out one by one and I would find out what what pulling the power, so I did that, but I had no luck. I don't really know where to go from here... does anyone have any suggestions?

This is a very broad subject.
The battery light should illuminate when the key is on and the engine is off. And should go out when the engine is running.

If you have problems, it could be from the alternator. The diodes control the light on the dash.

I've just replaced the voltage regulator, and it (the battery light) started just after the new one was put in. Is that why? Why would it do that? Do you think the whole alternator needs replacing? I just got a new battery because my old one wasn't holding a charge, and it drives for a few hours just fine, so I thought that the alternator was ok... I've been spending a few hours a day this past week researching on the web, but I'm still at a loss.

Did you incorrectly connect the battery recently?

Yes, the other day, on the morning that the voltage regulator was replaced, the battery was connected backwards... We drove about 5 minutes to where we replaced the v.r. and I didn't notice anything different then, but as soon as the v.r. was put in I noticed the battery light acting funny, and my stereo stopped working.