The tram and bus system in Potsdam is very modern and overall excellent though confusing. Potsdam is, together with Berlin and parts of Brandenburg, part of the VBB transportation network. That enables you to change trams and buses pretty much at will, as long as your ticket is valid for the zone you're in. The inner city of Potsdam is in Zone A, the outer parts are in Zone B, and the hinterland is Zone C. Be aware though, as Potsdam itself lies in Berlin's Zone C - Berlin's outer parts are Berlin Zone B and so on. A Berlin ABC or BC ticket will therefore cover your journey within Potsdam.
Tickets can be bought at ticket machines in every tram and bus. Most machines of newer type accept bills, coins, rechargeable "Geldkarten" cards and EC direct-debit cards; though some of these options may be temporarily unavailable and it's advisable to keep some coins at hand. There is an experimental ticket-less system (http://touchandtravel.de) which allows you to pay automatically by tracking your journey via a smartphone and is worth checking out if you meet the requirements. It's best to get detailed information about prices and zones at Potsdam's central station or on the VBB website. The transport, although confusing at first, is pretty logically laid out - each tourist attraction has its own bus / tram stop with the appropriate name and the staff of the VBB are extremely helpful, with most speaking English very well.
For tourists there are five main lines in and around Potsdam:
Schlösser-Linie Palaces Line:
Bus No 695 from Potsdam Hauptbahnhof - Bahnhof PirschheideWith stops for: The Historic Steam Engine House, Sanssouci Palace and Park, The Orangery, the Dragon House, the Belvedere, The New Palace and a path to the Charlottenhof Park
Krongut-Linie Crown Estate Line:
Tram No 92 from Potsdam Hauptbahnhof - Bornstedt KirschalleeWith stops for: The Dutch Quater, The Russian Colony Alexandrowka, the Pfingstberg, the Potsdam Biosphere and the Volkspark
Tropen-Linie Tropics Line:
From Potsdam Haupbahnhof - ViereckremiseWith stops for: The Historic City Centre, the Russian Colony Alexandrowka,the Pfingstberg, the Potsdam Biosphere and the Volkspark
Cecilienhof-Linie Cecilienhof Line:
From Potsdam Haupbahanhof take Tram Nos 90/92 to Reiterweg / AlleestraÃe, then Bus No 692 - HöhenstraÃeWith stops for: The Russian colony Alexandrowka, the New Garden, the Marble Palace, Celcilienhof Palace and the Pfingstberg
Filmstadt-Linie Film City Line:
From Potsdam Hauptbahnhof - Stern-Center / GerlachstraÃeWith stops for: Babelsberg palace and park, Flatow Tower, the Arcaded Court House, the Neubabelsberg Villa Colony, Babelsberg Media City and the Film Park.
