Here are some great resources I've found:
Voyage of the Dawn Treader Lapbook - Includes lapbook templates, activities & discussion questions, and alphabet copywork and coloring pages for the littles ones.
Educator's Guide - Walden Media has a reproducible guide to use with grades 5-8.
The Voyage of the Dawn Treader Literature-Based Unit Study - From Easy Fun School. Created by a 17 year-old student, this study is still in process. The first 3 chapters are ready, with chapters 4 & 5 due this week.
Online ebooks for purchasing:
Narnia: Voyage of the Dawn Treader Project Pack - From In The Hands of a Child. Gr. 4-8. They also have other Narnia packs available.
Voyage of the Dawn Treader Literature Unit Study & Lapbook - Currclick.com has this ebook 50% off through tomorrow, 12/13.
Viking ship - I had to add this awesome ship made from a milk carton. Be sure to check the other cool projects there too.