You will need a firewire card and cable in order to get the video from your camcorder to the computer. If your camcorder has DV-in then look for software that can transfer the edited video back to the camcorder (Adobe Premiere does this).
As for the software, I use Adobe Premiere but it is complex. Pinnacle do a good one (so I've heard).
If you do a search for video editing in the helproom then you should find quite a few threads with software recommendations.
Hope this helps