I work for Keepad Interactive, an Australian based technology company that focuses on interaction between people and how that can be augmented through the use of appropriate technology.
One of the products we sell and train people in is eBeam from Luidia, a device that easily turns any ordinary whiteboard into and interactive whiteboard with the help of a computer and a projector it is a very cost effective way to put a fully fuctional IWB in a classroom without sacrificing board space.
Luidia is always updating their software for this particular peice of hardware, but they have also been collecting resources to use with it, and now it is all available on their web page.
A huge selection of resources sorted by type and age group. It's nice that the company I sell for also take the time to research and find good resources to use with their hardware.