You need to have a decent machine with plenty of storage in order to handle video properly. This is not something to undertake with a dinosaur of a machine. There are a number of factors that play into making a good video out of anything, but the big three or four might be:
1. Storage space. We're talking Giga bytes and lots of them.
2. Throughput speed. You need a fast processor and faster bus speed. Talking on the order of Ghz for processor and 133Mhz or better for the bus speed. This is not a requirement, but it does speed things along and make things easier when editing.
3. Firewire capture capabilities are the best, but any method is better than no method. The adapters and PCI card mentioned in the previous post will be sufficient for the novice.
4. Good quality export capabilities. Most video software allows for export straight back to the camera. The better method is to burn to DVD or good quality video CD. The next problem is in burner speed. The slower the speed of burn the longer the disk takes to make (I know obvious...but we're talking on the order of hours if the video in question is high quality and long).
I can give more information, but this is good enough to start.