He is based on the historical Saint Nicholas, who distributes presents to sleeping children and adults who have been "good (nice)" all year and coal to those who have been "bad (naughty)" all year; traditionally during the night of 24.12.
You guessed correctly about the Dutch: The popular American form Santa Claus originated as a mispronunciation of Dutch Sinterklaas, which is a contracted form of Sint Nicolaas (Saint Nicholas).
http://en.wikipedia.org/wiki/Santa_claus#Overview
