These numbers are straight from the Gameday PITCHf/x data (accessed via Joe Lefkowitz's site) and have not been park-adjusted. As Mike Fast detailed in a Hardball Times post earlier in the year, there are some stadia in particular that have been showing higher than average velocities in the pitch data. In Fast's article, he mentions Kauffman Stadium, Coors Field, US Cellular Field, Progressive Field, and Fenway Park as being the parks with the highest velocity park factors on average. But, as Fast mentions, parks drift in and out of calibration over the course of a season, so it's impossible to take the velocity from any one game, apply the park factor to it, and get a certain result. Still, I feel pretty strongly that quite a few of these pitchers' numbers were enhanced by park. For example, of the pitchers that hit 100 mph only once, Morrow did it in Cleveland, Infante did it in Chicago, and Tejeda did it in Kansas City. And Chamberlain did it once in Kansas City and once in Chicago. So, please take these with a big old grain of salt.
Oh, one other thing I should mention. You may have been wondering, "Wait, didn't you say that Joel Zumaya hit 100 mph 230 times this year? Why does it say 225 here?" The reason for that is that there were some PITCHf/x errors that duplicated some pitches that I had not corrected for in my July post. I have now, so this should be slightly more accurate.