Check out the
Home Recording forums. These guys are very knowledgeable and helpful about any home recording issues you might have. One word of advice-make sure you understand every piece of your recording chain, from cables to mixer to soundcard to whatever-you-use. This will save you a lot of headaches trying to get everything to work together (speaking from experience).
FWIW, I have a 1.7 GHZ, Pentium 4, 512MB RAM, 80 GB hard drive, running Vegas Audio 2.0. I also have a Delta Omni Studio soundcard/breakout box installed, and use a Rode NT1000 mic. The Omni has an internal mixer that you access via the computer, so you don't need an external mixer. The mic preamps (you get 2 on the box) seem pretty transparent, but then I've never tried an ultra high-end preamp. I'm still getting used to it all, but I've gotten some spectacular-sounding recordings with it so far. That doesn't say anything about my playing, just that this equipment captures what I'm playing extremely well-which may or may not be a good thing!
Feel free to ask any other questions you have. Enjoy the search and good luck!