There is a shuttle that runs directly from the airport to South Lake Tahoe as well, if you prefer not to rent a car:
Trains, Buses, Airport Transfers - resource for different travel services
Blue Go Shuttles - in town shuttles and bus service $3 all-day pass
Demo tours - bus tours around the lake
Tahoe 360 - maps and webcams of the area
South Lake Tahoe Taxi Service
P.O.Box 2535 Stateline, Nevada 89449
Phone: 775-586-1181
Toll Free: 1-877-586-1181
Email: Dispatcher@StatelineTaxi.com