The best time to visit Amsterdam is June, for the Festival of Fools. Amsterdam has accommodations of all types from the luxurious, through regular hotels, pensions, hostels, crash pads and all stations beyond. There are so many things to experience in Amsterdam: the quiet graceful old town of endless canals, narrow houses and tiny streets.
Amsterdam is a city of fantastic surprises, a place crammed with sights and activities that seem to bear not the slightest resemblance to the picture of tulips, cheese, and wooden shoes. For information about accommodations try the airport bureau or the VVV (The Netherlands Tourist Office). They are quiet good at finding accommodations off the beaten tracks.
Related Link: Amsterdam and Canals