You can't go wrong with either The Villages Airport shuttle which runs on a schedule, or the Yellow Cab Village Airport Van 352-241-2000 which you call for a door-to-door pickup at no additional charge.
The Villages Airport shuttle will also pick you up at home if you're a Village resident for an extra $5 (per home not per passenger). The biggest difference between the two services is that Yellow cab also picks up travelers in neighboring communities which can add 30-60 minutes to the trip depending upon the number and location of the others. Of course if you're arriving after the last scheduled shuttle, than Yellow cab might be your only option.
Here's a link to Villages Airport Shuttle schedule:
http://www.thevillagestransportation.net/