Check out this free clip art site for educators. It is easy to use and has free clipart for most of your curricular needs. Great for the students, too.
After looking at a lot of sites that have information and/or lessons about the Smart Board, Teachers Love Smartboards is one of the best organized sites I've found. You can also sign up for weekly updates through your email account. Take a look at it.
Tammy Worcester is a teacher and presenter at many technology conferences. Her tips include using the internet, Powerpoint, Word, and Google with students for fun and learning. Check out this site.
Here is an example of one of Tammy's Tips of the Week:
This tip explains how you can save a YouTube video (which you find at your home) to a format that will run on the school computers. This will allow you to use YouTube videos in your classroom. As you know many YouTubes are educational, but many are not, so it is blocked here at school. This is one way to work around it.