Wendersnaven.com (a resource for nwn2 builders)

Sunjammer posted an excellent guide about world maps on nwvault. From his description on that page:

The NWN2 World Map System provides an exciting new interface for representing long distance travel in your campaign. However as it introduces several new concepts and requires some scripting knowledge the World Map System has proven to be rather difficult to master.

The World Map Guide is designed to help you integrate a fully function World Map into you campaign with the minimum of pain and suffering. When complete the World Map Guide will take you every step along the road from constructing your first World Map to overhauling the World Map GUI.

You can download it here:
http://nwvault.ign.com/View.php?view=NWN2Tutorials.Detail&id=54

You may also want to check out Sunjammer's website.