Sites that have great content for use with an interactive whiteboard:

All Ages:

Art Rage (download)
The Artist's Toolkit
Arts Alive Music Activities
Childrens Museum of Indianapolis
Create a Graph
Daily Dose of the Web
Earth Cam
Free Rice
Global Tribe
Google Earth
Grow a Tree
How Stuff Works (quizzes and activities)
Intel Templates
Interactivate Math Activities
Kids Jungle
Magnetic Poetry and Mad Libs
A Math Dictionary for Kids
Music Theory
My Pyramid (nutrition)
National Geographic Map Games
National Library of Virtual Manipulatives
PBS WayBack Activities
Simulations (ex: frog dissection)
Spelling City
Tutorial for Creating a Game Board
Virtual Field Trips
Vocabulary game templates
We Give Books
Word Play

Younger Students:

Analog Clock
Cloud Dreamer
Colonial House Dress Me Up
Design a Panda Habitat
EdPax (activities to download)
English Games
GeoSpy Geography Game
Interactive Clock
Kelp Forest
Learning Clip Primary Math Activities
Learning Planet activities
Learning Planet Games
Make a Tide Pool
Panda Challenge
PBS Kids Games
Rainforest at Night
Read, Write, Think activities
Scholastic Interactive Resources
Simple Machines
That Quiz
Thumb Piano (Africa)
Times Educational Supplement iBoard Activities
United States Map interactive
A Walk in the Forest
Walk in the Woods

Older Students:

Asian Games
BBC Algebra
Cabri 3D Gallery (geometry and physics)
Design a Parachute
The Drake Equation
Drive of Your Life (careers)
EdHeads Engineering Activities
Forces Lab
Free Poverty
GeoTerra (eco-imagination)
Heritage Explorer (images and activities)
How to Read Scales
Hunt for the SuperTwister
Iraq Navigator: Mapping the Conflict
The Jamestown Chronicles
Let's Make a Microbe
Making Vaccines
Manga Shakespeare
Materials Lab
Molly on Board (communication skills and teamwork)
Nathaniel Hawthorne
Nobel Prize Educational Games
OxFam Education Resources
Pi: Infinite Secrets
Saving the National Treasures
Sim Sweatshop
Two Steps Forward, One Step Back (Women in Kenya)
Who's Who in Darfur: The Geopolitics of Tragedy

Where are you as an interactive whiteboard user?

Beginning User
Adaptive User
Advanced User
Teaching and manipulating
Teaching, manipulating, and student interaction in a very visually effective way
Display - overhead projector
Use dry-erase markers for annotating what's on the screen
Teacher is the primary user
Unsure, not confident with basic tools in Notebook software
Uses for seatwork/bellwork/housekeeping then turns off for rest of class
Used primarily for showing videos
Uses stylus markers for notes and examples in Notebook
Notebook Galleries are used on a regular basis
Notebook is used on an hourly basis
Most Notebook features used
Visual presentation limited to notes, study guides, worksheets or other scanned materials
Numerous Notebook features are used with ease, including advanced features (such as recording, spotlighting, highlighting, etc.)
Students interact with manipulatives, maps or other portions of interactive lessons
Students annotate in Notebook, on the Internet
Interactive lessons are developed and used on a regular basis
Notebook, Internet, emulators and other projected programs used on an hourly basis
Interactive whiteboard and projector are used in effective visual presentations (images, maps, Internet, video integration, SMART Ideas, interactive Powerpoints, saved annotations in productivity software)
Has experimented with improving skills through training sessions, downloading templates and lessons
Knows basic
Another rubric for teacher use of interactive whiteboard:

Hardware Specific Resources (SMARTboard, Promethean, Mimeo, etc.)

SMART's Lesson Exchange

SMART Lesson Activity Toolkit Tips & Tricks
Quick Reference Guide:

Tons of Templates (about 650) for SMART board

Promethean Planet

Notebook Software Basics 2 Minute Overview
Tips for Teaching with Interactive Whiteboards
10 Ways to Use Your Interactive Whiteboard More Effectively
Tara's Tuesday Tips
Get Smart with SMARTboards
Teaching with SMARTboard
The Whiteboard Blog
Interactive Whiteboard 101