Yeah King uses Vegas. He has an editing package out that costs money, but is definatly worth buying from what I have heard if you want to get good. He also has a youtube video of the basics.
http://www.youtube.com/watch?v=M5-uXHPemwo
My capture card was around £120 and you can get vegas for free.
PM King to see if he still has his pack. I think it only cost $10 or so (£5).
If you gather all your clips on your file share and on your account, somepeople may capture for free. Some charge. Just explore the various halo sites and you may get lucky!