Math is Fun
I wrote a program to help put a tangible spin on algebra and it's called Algebra Vision.
There's a demonstration of it at YouTube: http://youtube.com/watch?v=T9ZAHIfTIaM
Basically, it evolved out of trying to explain algebraic concepts to my friends in college. They were more visually inclined, so I tried to cater to that mindset.
There's a free downloadable demo at http://www.algebravision.com
Let me know if it helps your students! I wrote it myself, and want to get feedback to make it better and better.