I record with ingame commands in Counter-Strike. You have to start your demo and type "startmovie NAME FPS" to start recording images. When you want to stop your "scene", just type "endmovie". Now you have like 1000 picture. Put them together to a videofile. For that you can use the programm "VirtualDub". It's not that easy to explain it that understandable, but you may try to google for some tutorials or something!
http://www.file-upload.net/download-1457476/candy_nuke_ace.wmv.html
Regards