Oh my God, I can't believe it. I just realized that I already had one of those mini phone plugs lying around near my computer. It's from Radio Shack but I have no idea when or why I have one. Just looking at the picture posted earlier of the cable, somehow it hit me that it looked similar to some of the extra cables lying around my basement that I seemingly had no use for. But now I can test it out without worrying about having to return something if it doesn't work.
But that brings me to the next question. What do I do with the video afterward? What are my options for rendering it to a new file after I've edited a bunch of clips in Vegas? Before, I would just make an avi file that would keep the video quality exactly the same, no further compression. For burning to dvd, I would use Sonic Mydvd. It has only one automatic write speed for dvd but it actually works out well. As I later realized, the auto write speed compresses the video so that about 4 times as much video can fit but it still looks really good. (Two 7 gb avi videos take up a little more than 3/4 the write space available for a single layer dvd in the program) I'm fine with that because it means I get to keep a video master on the computer that's identical in quality to the raw captures that make it up.

But I'm afraid rendering a losslessly Huffy compressed file to avi will actually make it bigger by not maintaining the lossless compression. I recently took an mp3 file that was 5 minutes and 6 mb, cut it down to 3.5 and re rendered it as a lossless wma. It didn't sound that great so I wanted to make sure I didn't decrease the quality further. The resulting file became an astounding 57 mb. How could it need more mb than the file originally was before? Screwing up audio like that is not too big a deal because it doesn't require anything close to the space needed for video. Am I right to be afraid of doing that with video? Are there any kind of lossless audio compression codecs out there, btw?

The other thing is I might be interested in a more advanced dvd burning software. (I've heard a lot of good things about Nero) Would other dvd software have auto compress write speeds available like Sonic does? If they don't I would have to learn how to use a lossy compression from the Vegas rendering. Something I've been hesitant to do. I know it's possible to throw away a lot of data and lose only a tiny bit of quality but I'm not sure how easy it would be for me to find such a setting. I tried mPEG 2 compression once on a short video segment and it made the video look like it was shot using the low light (not nightshot) mode on a video camera. I know mpeg 2 can look a lot better and is even used by professionals, but I have no idea what makes the difference.

I'm going to see if I can get audio now that I know I have the mini phone cable and now know where it's supposed to go. Thank you all so much for your help. I'm amazed that I've gotten this far as I have never considered myself good with anything on a computer.
EDIT: Turns out the mini cable will fit into a computer plug but the 2 in jacks are not the right size for RCA red and white audio cables.