Utrecht University has an extensive website in English. The section "arriving and living" has sections amongst others on: The Netherlands, Utrecht city, Getting there and around, Accomodation, Visa, residence permit and city registration, Money matters and Health and safety.
NUFFIC, the Netherlands organisation for international cooperation in higher education, has general information about visas, residence permits, housing, working while you are here and problems. They also have links to many documents that you can download.
Euraxess is an information and advice point for internationally mobile researchers wishing to come to or staying in The Netherlands. On this website you can find information on funding opportunities, job offers, immigration procedures, social security and tax issues and other topics relating to researcher mobility.
The Immigration and Naturalisation Service has a very good website in English. It has a Residence Wizard which enables you to find what the requirements are for coming to the Netherlands or extending your stay.
The Income Tax Office has a very good English website (and in German).
Expatica is a website in English specially for expatriates in the Netherlands. If you register your email address then you get emails with the latest developments in Holland. It gives useful current information on all aspects of living here.
Utrecht has a good website in English about the city.