So, when I want to help a teacher or a school get over the hump and begin making effective use of Web-based resources, I look at what they are doing, at their curriculum, and then make some suggestions. For instance, high school chemistry teachers know the importance of an up-to-date periodic table and make use of it every day, making the WebElements Periodic Table a natural. For an early elementary-school classroom teacher with the clear focus on foundational literacy, Starfall makes complete sense. And all teachers use maps in their teaching, making National Geographic's Xpeditions Atlas a clear winner.
With whiteboards practically being a ubiquitous tool these days, leaving chalkboards behind in their own dust, how about an interactive online whiteboard, supported by the folks at General Electric, that allows you to draw in a collaborative environment? Rather than trying to explain it, I have to just urge you to try it. Trust me: If you know how to use a whiteboard, this is going to make sense! And there is so much more, because it is digital. Have fun, and please, let me know what kinds of cool things you accomplish with it!