The links AccursedDelphi should help if you've read them.
As for the Street Fighter II Turbo thing... My guess is that when upping the speed the CPU is just working harder to increase the speed (and probably its frames per second). You can see this happing quite often on old emulators on a top spec PC where a frame limiter is needed to keep the game playable. Quite good if this is the case since the SNES has a rather slow CPU... 3.84Hz or something

It also has 2 or three other pre-set slower speeds but this isn't the time to go into depth...
Sinzer was totally correct at how the naked eye can notice FPS. Movie reels found in cinemas only have 24FPS for example and thus need a conversion when pressed on DVDs (it also needs a 4% speedup on PAL DVDs to keep things in sync).
PAL is a standard accepted in Europe and runs at 50Hz, 25 fields a second.
NTSC is mainly used in Japan and America and runs at 60Hz, 30 fields a second.
Both are interlaced and consists of two fields flickering/interlacing to create a solid picture... So for example the first field would display the odd lines "1 - 3 - 5 - 7 - 9 - 11" etc and the second field would display all the even lines "2 - 4 - 6 - 8 - 10" etc.
1-3-5-7-9-11 Odd field
-2-4-6-8-10 Even field
or
{#}_{#}_{#}_{#}_{#}_{#}_{#}_{#}_{#}
_{#}_{#}_{#}_{#}_{#}_{#}_{#}_{#}_{#}
Hmm... crap examples... So much for corurier being identically spaced out >_<
Anyway, these two fields combined creates an illusion of "one solid" image. On PAL TVs the scan rate is at 50Hz and so the screen is filled with odd and even lines 50 times per second. For NTSC the scan rate is 60Hz and thus the screen is filled 60 times per second.
More differences between the two display standards are colour and resolution. PAL has an extra 100 lines or something (please correct me on this since I always forget) and those lines are responsible for the 17.5% slower gameplay and borders. With a 60Hz option the screen is all used up and games are played they way it should be.
So to answer Keysers question if SF2T wuld run the same on PAL and on NTSC consoles.. The answer would be no since the fastest setting on both would make the NTSC version the fastest by some margin.
Also to add... The magic of progressive scan - This signal produces one full field at a time and not an interlaced one. So instead of seeing one half of the image, then on the next field the other half of the image (interlaced) you will see the full field at any given time - Much like how you would see pictures on a movie reel. The benefits of progressive scan is obvious and Europe really needs to get its arse into gear and support this full stop.
Anyway.. thats enough ranting for now. I can't remember all the specs and details all the time so feel free to correct me ^_^