Yes, if you know which bus you are suppose to take you can go just about anywhere around Orlando. I know people from the UK who use the Lynx bus from the airport and around to the theme parks for the whole trip. It is cheaper than a taxi but it will take a lot of time. You can try the trip planner on the websitehttp://www.golynx.com/?id=1155574
Lynx is the bus system in central florida. It will take you from the airport, but all of the different buses go to different places, just like every other bus sytem in the US. Make sure you know where the bus is going before you get on one.
DON T TAKE IT!!!!!!!!!!!!!!!! It will get you horrendously late! Unfortunatly, Orlando has horrible, and I mean HORRIBLE mass transit. I reccomment hiring a car service.