The Essential Vermeer provides a wide range of in-house resources for studying the work and life of Johannes Vermeer.
This site is simply awesome. It contains a huge amount of information on the great painter: no matter what you’d like to know, you’ll find it here. I wouldn’t know what to highlight, but I found very interesting the articles on the master’s technique and those on the palette he used. If you feel like an expert after all the reading, you can participate in the controversy about the authorship of the recently attributed “A young woman seated at the virginals”.