The first place to start when you are looking for ideas to use on the SmartBoard is the Smart Exchange You can search for lessons by grade, subject, and file type. The best part is that it is all free! Teachers are such a sharing group! Even you find something you like, but would like to change it, it is quite simple. Just download the file, open it, and tweek it. I suggest saving your new version with a different name. For instance, if the file is "orchestra instruments", I might save it as "orchestra instruments cje version" or "orchestra instruments 030512"(which indicates the date I changed it).
Here are some other resources for SmartBoards: