I´ve filmed few halo videos myself. I´ll give u info from my own filming knowledge. Here´s a few links to download programs that are REALLY useful on filming!
http://www.fraps.com/download.php That´s the FRAPS program. it´s pretty good to start practising filming with that! The free version kinda sucks, by the way, U´ll see why. There´s another free game-filming programme, GameCam:
http://www.planetgamecam.com/?locid=download That´s harder to use than FRAPS, I think, I prefer the Fraps first. BUT. If you´re not a freaking SAINT, you can just download the FULL version of FRAPS. but ILLEGALLY!! I regret I got the free version, cuz´ if you get the free one, you can´t download the full one illegally after that, it doesn´t work after that! (trust me.) (It sucks.)
BUT!! If filming, you could use some EXTRA programs to make film quality and get more possibilities about filming:
http://hce.halomaps.org/index.cfm?fid=997 Halo FlyCam is an EXCELLENT program to use on filming!! It gives you a chance to fly EVERYWHERE you want on the halo map, with no HUDs or Shield Bars and stuff.You´ll learn to use it after a while.
http://hce.halomaps.org/index.cfm?fid=1230 "No Text Mode for Halo PC/CE" Is a good invation, too! It allows to take off the texts in corner of the halo games or put it back on. It look kinda funny if you are seeing the text while the filmings! (WATCH THE Instructions from the site!!)
http://hce.halomaps.org/index.cfm?fid=2910 That´s a good program! Look at the description. It tells you.
There are many other film things you need to learn. Don´t worry. I´ll teach you!
For the editing of the video clips, you can just use the WMM. (Windows Movie Maker) It´s already on your computer, if you have the Windows XP.
I´ll teach you more when we can talk.
-SoF-A#-Drop