Well I've been looking into this stuff myself lately since I've been considering doing a let's play. (Recording of your gameplay and providing commentary)
Essentially the process goes like this:
Record using Fraps or Camtasia or the like.
Then take the raw footage (which ends up being several gigs in size)
Then encode it in a program like AVS Video Encoder to bring it down to a reasonable size (A couple hundred MB I think)
Then upload to Youtube.
Here's a software resource post on a forum dedicated to let's plays and the like.
http://voltronarmy.com/forums/showth...s-For-LPers%29
Infact that entire forum should be able to have some information for you.