We went to see Pisa after visiting Florence. That was obviously too tiring for my schoolmate Ales who was sleeping tight like a baby on our bus on the way to Pisa.
It only takes about an hour to get here from Florence.
From the train station, you will have to take the bus to the Leaning Tower. Walking to the tower is too far. Take either the #3 or A bus to the tower. Get off at Piazza dei Miracoli.
The tickets can be bought at the train station at newspaper stands for 0.80 euros each. They are valid for 60 minutes after stamping.
It's a short 1/2 mile walk from the airport to the Pisa Central train station and the Hotel Roseto (A hotel which I recommend). From the train station and hotel, the #3 bus line will take you to the Piazza Del Miracoli, where the Leaning Tower and other main attractions are located. When there, I took the bus to the Leaning Tower, and walked back across the town to the hotel. This was nice, it allows you to see more of the city from foot and see things you wouldn't normally see otherwise. It took me about 30 minutes to walk from the Leaning Tower to the Train Station which was near my hotel.
I enjoyed the way to Pisa in a tourist bus. We rode over the mountain pass - if you visit Italy in March, like me, on the way to Pisa you can see the seasons change: green spring - white winter - golden autumn.
I took the train from Florence. It was an hour ride.
Then I took the bus #3 directly to the tower. The bus fare costs 0.77 Euro one way. It's better to get round trip bus tickets at the train station because sometimes you don't get to find a kiosk around the bus stop.
The bus system in Pisa is the best way to travel around... The city was much larger than I expected. You can buy tickets to ride at the local tabacco staores. Be sure to check the route the bus takes as not all of the buses return the same way they came. The tourist information (to the left as you exit the train station) can tell you exactly where each bus runs.
Bus # 3 will take you from the airport to Campo dei Miracoli in about 20 minutes. The same bus stops at the train station on its route through town.