Trefor suggested a web site that has some really effective simulations: http://phet.colorado.edu/simulations/
I don’t have access to a computer lab, so you won’t see a lot of computer based lesson from me. If anyone has lesson plans to be used with these or any other simulations, I’d love to post them for everyone to use.
I’m going to see if I can get Trefor to submit his lesson plans for this 
site. Check back here and see if I was successful.
I just found this package through some random surfing. It’s called Phun and it’s a simple graphical world builder with a real physics engine underneath. There is a decent online tutorial and a pretty decent online community to share ideas and solve problems. The download is only 2.8MB, it loads up fast and easy.
Phun can be found here: http://www.phunland.com/wiki/Home
The software was created by Emil Ernerfeldt as part of his masters thesis at Umea University. He calls it a 2D Physics Sandbox and I can see why. You want to take yours shoes off and just play in it all day. Since its creation, Emil has gone to work for a software company where he continues to develop Phun.
Phun is free for an individual to use, but not free for commercial use. Emil made it clear, however, that Phun is free for educational use. I plan to install in on the computers in my classroom and give assignments and perhaps extra credit for designs that demonstrate the principals we are working on in class. There is no reason why my students can’t install the software at home and bring in their creations.
