Check out:
http://recursive-labs.com/blog/2012/07/27/expeyes-electronics-lab-in-your-pocket/
ExpEyes is a wonderful tool ... the developer (who is a Physicist and Free
Software enthusiast) has put in a tremendous
amount of work in getting it to its current state. We now have a small
community of science
teachers behind the project; it is hoped that the Free
Software/DIY/hobbyist community in India
will take the project forward in the coming days ...