Fodors.com
Find out when and how much to tip in the Netherlands.
http://www.fodors.com/features/nfdisplay1.cfm?name=stt/010124_stt_tg_netherlands

Hotels Holland
Offers basic advice on tipping etiquette in Amsterdam.
http://www.hotels-holland.com/amsterdam-info/adam-6tipping.htm

iAgora.com
Tipping etiquette in Dutch clubs.
http://www.iagora.com/itravel/icities/netherlands/amsterdam/si_gen.html?review_id=361