2000 gets you everywhere (summer 2006), although it's not totally unreasonable to pay an extra 1000 really late at night.

Don't forget about the petrol prices - they've gone up since 2005. I live here, and speak khmer, but I'd pay 1500 riel for a short trip and up to a dollar to go across town in the daytime. When did you last see a well dressed, well fed motodriver?

Petrol prices have gone up a lot, and so has the cost of living. The best way is to talk to the moto driver before you travel, and negotiate a price that you are both happy with. If a driver sees you as a good customer, they will do their best to look after you - waiting until you are safe inside before driving off, for example. If you want a good, fair price, look for the drivers on the old Daelims, as they are generally safer and cheaper than the ones on shiny new Hondas.