Karen Fasimpaur has a new blog post on getting involved in open textbooks. Fasimpaur suggests a few online projects as well as contacting local district curriculum administrators. From the blog post:
People have asked me how they can start getting involved in open textbooks. Here are a couple ideas. First, go explore Wikibooks and especially Wikijunior. There are tons of open textbooks here that you can use, edit, contribute to, customize, or even create your own.