Geneva, like most cities in Switzerland, is a marvel of public transportation efficiency. Transports Publics Genevois (http://www.tpg.ch/Interne...) provides frequent bus, tram, 'mouette' boat, and suburban train service to within a block or two of most locations in the city and canton.
The law changed this year and anybody staying in a Geneva hotel/hostel is entitled to a free daily travel pass for the local Transport TPG. This is provided by the hotel. Read more about it in the section "by bus".
By car
If you want to explore the mountainous countryside or go skiing in one of the ski resorts in the Alps, getting a car is a better option. Numerous local and international car rental service providers operate from the airport. They provide customized traveling services to the needs of tourists visiting Geneva.
By bike
Geneva is a great town to get around in by bicycle. Except for the old-town, the city is fairly flat, and though there are some streets that are dangerous to ride, there is almost always a safe, fast route to your destination. If you want to know the best routes, you should get a copy of the beautifully designed VELO-LOVE plan de ville, which is available at all bike shops in Geneva, or by writing to: [email protected] or calling +41 22 418 42 00.
A social organization called Genèveroule (http://www.geneveroule.ch/) lends bicycles free of charge for four hours and then a fee of 2 CHF per extra hour, from 30 April through 30 October. A passport or identity card must be shown and a refundable deposit of 20CHF is required. Six stations are located along the lake, behind the railway station, in Eaux-Vives Terrassière the Plaine de Plainpalais and at Carouge. While this service is quite convenient, be sure to bring ID and contact information, including hotel phone number, to speed up the paperwork.
Otherwise, if you're looking for a road bike or a trekking bike, then there is a shop very near the train station called "Bike Switzerland" (http://www.bikeswitzerlan...)
By Tram
Geneva has an expanding network of super frequent trams. Many lines have their hub at the Cornavin train station, a few others at Place Bel-Air on the old-town side of the river. If you did not receive a TPG / Unireso card from your hotel, you will need to buy a ticket from one of the ticket machines located at every stop before boarding the transport. Tickets cover both trams and buses.
By ship
The "mouette" service is included in the TPG / Unireso card that tourists receive free of charge from their hotels. This is a nice way to get from the Pâquis station near the Quai du Mont-Blanc in the north to the other side of the lake, e.g. to the Eaux-Vives stop near the Jardin anglais. Boats run every 10 minutes. See (http://www.swissboat.com/...) for more information.
By train
Suburban trains to outskirts run every half hour during the day and every hour after 8PM. The last train to the eastern terminus, Coppet, leaves at 12:03AM. Though these "Regios" mostly serve commuters, at least two of their station stops, Versoix and Coppet, have several good restaurants and historic main streets. There is also another suburban rail line: the RER Genève, which goes from Cornavin to La Plaine, sometimes continuing to France 2 stops from La Plaine. As with buses and trams, tickets must be bought before boarding the train. If you are only travelling with the canton of Geneva, a bus/tram ticket is valid on the train and vice versa; travelling further afield will cost more unless you buy a so-called regional ticket, which also includes parts of Vaud and France.
Districts
Old Town vieille ville and St. Gervais
Paquis
Plainpalais
Hopital
Eaux-Vives
On foot
The old-town can be easily visited by foot starting anywhere around the tour boat dock on Lake Geneva. Crossing the bridge Pont du Mont Blanc, you'll get to the English Garden with the famous flower clock and a sculpted bronze water fountain. Then you can cross the street Quai de General Guisan and go up the hill on Place du Port and Rue de la Fontaine and up the long stairs passage and end up behind Saint Peter's Cathedral. After visiting the cathedral, which is Geneva's well-known landmark, you can exit the courtyard and be right in front of Geneva City Hall. From there you can easily walk down to the Bastions Park where you can find the famous Reformation Wall memorial. This park is very quiet and romantic, especially at the beginning of the fall season when the leaves start falling. See this walking route in pictures (http://www.e-vlad.net/pho...).
By bus
Tickets, which cover both trams and buses, must be bought from ticket machines located at every stop before boarding the transport. Some bus stops do not have a ticket machine, but in that case you can buy a ticket on board the bus itself.
Tickets cost 2CHF for a short hop three stops or less, or a one-way crossing of the lake. 3CHF for one hour with unlimited changes on tram, bus, boat, and rail within greater Geneva, 8CHF for a day pass valid from 9AM to midnight, and 10.80CHF for an extended day pass valid from the time it is purchased until 5AM the next morning. Holders of the SBB Demi-Tarif/Halbtax card get 20-30% off these prices. The ticket machines do not give change, if you have over paid, keep the ticket and take it to a TPG office located at the airport, Cornavin railway station and in the middle of the rond-pont de Rive, where the difference will be refunded to you.
Observe that you will need to purchase a separate ticket if you are traveling outside the canton of Geneva - ie. to or from France or the canton of Vaud. "Ordinary" tickets and day passes are only valid inside Geneva. Bus stops in France that are served by the Genevan transport authority do not have ticket vending machines, instead you have to buy the tickets from vending machines on board the bus when traveling from France.
Since January 2008, if you stay in a hotel, hostel, or on a camping site, you will get free public transport. Typically, you will receive a Unireso Geneva Transport Card at check-in. It will be authorised for use for the length of your stay and like a ticket one gets in the airport upon arrival it is valid for Geneva and suburbs including the Unireso network. You are supposed to carry your passport or identity card with you at the same time, to ensure validity. The ticket is valid on trains as far as the airport. One pass is valid for a maximum of 15 days, and it is valid also on the day you check out from your place of stay, which is handy if you have a late flight and want do some sightseeing or shopping.