Some usage hints:
– Start your game in fullscreen in order to record it (I couldn’t record windowed game)
– Download VirtualDUB to compress the recorded video
– After launching the prog, remember to use “no sound” option
– I used “video > compression > Indeo video 5.10″ with “80% quality” (thanks to Tim for this hint) to get the file size lower
– File > Save as AVI and you are done.