First you'll need to get the video from your camera to the computer. Do you have a Digital-Hi8 or just a regular Hi8?
If your camera does not have firewire you'll need to get a bridge like this in order to transfer the video: Dazzle DVC120
Assuming you have windows XP check out Windows Movie Maker II
(it's FREE). This will give the opportunity to learn the basics before dropping $300+ for an editing application.