One of the best baseball movies to watch with your kids is The Rookie. It's based on the true story of Jim Morris (played by Dennis Quaid), a Texas high school science teacher and former baseball player who attempts a comeback at the ripe old age of 37. The supporting cast includes Rachel Griffiths, Brian Cox and that kid from Two and a Half Men. Plus a good mix of old coots for local flavor.
The baseball is believable (not always a given in baseball flicks), the story is inspirational (for those of you who teach science in Texas and can throw 98 mph) and there's just enough beefcake for the ladies (Dennis Quaid likes to take off his shirt - so does his brother Randy, by the way, which makes for a very strange lesson in genetics. But that's another post in another blog).
Most importantly, it stands up to multiple viewings - perhaps the greatest criteria when it comes to movies your kids will watch.
PS - yes, it's directed by the same guy who made The Blind Side, but there's no baseball in that, so we haven't seen it.