LostZeal,
Sidd Finch was a fictional character, an April Fool's joke by a journalist:
http://en.wikipedia.org/wiki/Sidd_Finch I've read credible reports citing Bob Feller as throwing the fastest pitch ever in an MLB game, 107.9 mph in 1946 at Griffith Stadium. Other reports say that Nolan Ryan was the fastest in an MLB game at 100.9 mph in 1974. I believe that Perfect Game has had at least one HS player throw 103 mph at one of their events.
What's the fastest? I'm not sure, but I think something in the range of 103 to 105 mph is likely.
Julie