Even in North America, the bus can sometimes be a viable choice for getting around, particularly if you want to avoid driving, yet wish to visit small towns. For instance, people who want to visit Key West and who hate flying will be glad to know that they can take the train to Miami, then a bus (twice daily) to Key West, along the ultra-spectacularly scenic Overseas Highway. In the USA, contact Greyhound Bus lines at 800/231-2222 or www.greyhound.com.
Within Europe, buses provide the cheapest form of transport between major and minor cities. In Amsterdam, especially, you can board coaches for points as distant as Istanbul, as near as Paris, for a fraction of the price you would pay for airfare, and about half what you might pay for coach seats in trains. Look in the English-language alternative weekly papers in Amsterdam for the latest fares, or just go to the Damrak (including Rokin Street), where a couple dozen bus, rail, air and package "bucket shops" are located, each trying to outdo the other in bargains. The largest operator in Europe is Eurolines, which you check out online at www.eurolines.com.
Another option for transcontinental European travel is Busabout, a sister company of the reputable Trafalgar Tours. Busabout offers a flexipass program that allows you unlimited passage between 66 European destinations for the duration of the pass, which is available in multiple day segments (6-day, 10-day, etc.). You can contact them online at www.busabout.com.
Young backpackers frequently take the bus between cities in Asia, Africa and Latin America, but you should be fit and healthy, plus willing to undergo unscheduled stops, termination of the trip halfway, and other unpleasant surprises. If you do not wish to play the daredevil, confine long-distance bus travel to North America and other English-speaking areas (Australia and New Zealand, for instance) and Europe.