Equipment: You could just have a baseball bat, baseball, and glove and play but, in the major leagues, you need some more equipment.
You need:
A baseball glove (different kinds for different positions)
Baseball bat (wood only)
A cup (protects you from baseballs)
A baseball jersey (every team has a different one)
A baseball hat (every team has a different one)
Baseball Cleats
Optional
Shin guards
Elbow brace