A pitching machine is a gadget that can pitch balls, either baseballs or softballs, with a consistent speed and placement. They are great for batting practice so hitters can develop their skills. A machine will often have a dial so you can adjust the pitch speed. Some machines have multi pitch settings, so you can practice breaking balls, fast balls, and more as you choose. If you get one, you should try to get a ball feeder with it. With a feeder, the pitching machine will send balls your way at a fixed interval. This is often about six seconds or so. It is usually a good idea to also get some extra balls with one. Also, some machines can be used both for softball and baseball. If you want to use one for softball as well, make sure to get a model that can handle double duty.
If you have more questions and want to see what to get with your pitching machine, see this faq.