I also really liked Fever Pitch.
Another good baseball movie that I liked that hasn't been mentioned yet was "Little Big League"
, where a kid inherited the Minnesota Twins and decided to manage them himself. The actual baseball scenes in that movie were the best I've seen and the quiz the assistant manager gave the kid to determine if he was knowledgeable enough to actually manage the team was quite convincing. Good Flick!!!
On the opposite end of the spectrum, anybody ever watch "Rookie of the Year"? You know, the movie where some annoying 10 year old kid breaks his arm and when it heals, he's able to throw 100 mph and pitches in the big leagues? What a piece of crap that was.