There are some fantastic guides out there aimed at newcomers to machinima editing.
To get started with recording your footage (the most important bit of course), you could take a look at:
http://www.mmorpgforum.net/showthread.php?t=331
Once you've got that sorted, check out:
http://forums.curse-gaming.com/showt...ighlight=fraps
Remember, your first videos are unlikely to be jawdropping, but everyone has to start somewhere and as you keep working and learning new techniques, you'll improve vastly!
Good luck!