By public transport

Dutch metros, trams and busses all use the National Tariff System, which is quite cleverly used all over the country (as the name implies). It is an integrated scheme for ticketing and it means you can buy tickets for the bus in Groningen, for example, and use them on the tram in The Hauge. This system does not extend to the national train system, although you may use these tickets for certain section of train line, such as between stations in the same city.

Strippenkaart

To use a tram, subway or bus you will first need to buy a strippenkaart, shown here.

This is your tickets. Strippenkaarten are widely available at many places including supermarkts, tobacconists and tourist offices. They consist of numbered lines, called strippen. The distance counted in "zones" determines the number of lines you must use. The mininum number is 2 lines, one for the basic charge, one for the first "zone" of travel. 

If there is a conductor, he or she will know how many lines to stamp. Alternatively, there will be maps at the bus or tram stop or inside the vehicle.

If you do not have a strippenkaart when boarding, you may also buy one from the conductor or from the driver. This will be more expensive though. Keep one in your wallet, it remains valid for at least a year.

Strippenkaarten are sold with 15 or 45 strippen. The smaller, more expenisve, denominations (2, 3 and 8) are available on buses and trams.

If you plan to use public transport regularly, a monthly or yearly ticket, or seasonal ticket might be worthwhile.

OV Chip Card

The OV chipkaart (OV Chip Card) has recently been introduces as a new means of payment for the public transport system in The Netherlands. The smart card is the size of a bank card and contains an invisible chip. You can charge your OV Chip Card with credit in euros with which you can travel anywhere within The Netherlands, or with a travel product such as a single or season ticket.

In some cities, the strippenkaart has already been replaced by the OV Chip Card. This means that a strippenkaart can no longer be used in those places. In other locations, you can choose between using strippenkaart or OV Chip Card for your journey.

More Information

OV Chip Card:
Check the official website of the OV Chip Card for lots of information on how to use it.

GVB:
The website of the public transport company of Amsterdam offers maps, timetable, and other useful information in various langages.

Door-to-door journey planner:
Check the national public transport door-to-door journey planner for an advice on how to get from A to B. This includes travel by train, bus, tram and metro.

Wikipedia:
Wikipedia has both a page on the National Tariff System with plenty more information on how to use a strippenkaart and on the OV Chipcard.