Learn Dutch Free with Wikibooks
The Wikibook for learning Dutch contains free lessons for several skill levels. There is grammar information including adjectives, adverbs, gender, negation, preposition, pronouns, sentences, tenses and verbs. There are also several texts which are used for instruction.
Wikibooks is a great concept. Like Wikipedia, Wikibooks consists of content that is public domain. That means that anything there is reusable in any fashion, such as for teaching.
So feel free to use and reuse and redistribute this free Dutch language learning content. You can even help improve it if you feel so inclined.