A couple years ago, I used
Snagit (an older version though) to do movie capture of "The Sims." At the time I had a 466 Mhz Celeron, so the best I could do was 640x480x15fps with reasonable speed, although the program could do higher resolution. Snagit is $40 to buy, but their trial lets you do everything until it expires (and then you can't save).
The quality of video you get really depends on how fast your CPU/memory and harddrive is. Copy data off the screen is actually very slow to do compared to copying data to the screen.