Resources:
K-3 Web Site... ings of the day (Kinderworks)
Web2.0 Cool Tools for Schools
RedZee (Visual Search Engine)
Teacher First Online Tools
Mrs. Stamp's Kindergarten Links
Mrs. Austin's Kindergarten Kids: This is a simple, but powerful example of using a blog to increase communication. Students could help update and publish the blog.
Kinder by Kim: Another wonderful approach to a web site... especially if kids are taking the pictures.
Ms. Jacoby's 2nd Grade: A wonderful teacher website for K-2 teachers... a model of several years of development.  Pick two-three ideas and you will have a great start to your own.
Green Gables Elementary: Kindergarten website