Recording

[Mime]

make a replay in-game. use a screen capture program like fraps to record exactly what you want (you can remove the healthbars, chat, etc.).
then edit what you recorded using the screen capture program with a editing program such as sony vegas, or if windows movie maker.

^ Make sure to make the game play full screen.

[serpento]

this is a really neat guide if you are unfamiliar with the controls in replays! its very useful!

( i take no credit. therefore this video is not mine )

[4shadow]

use your cell phone.