The Math Learning Center (publisher of Bridges in Mathematics) has a free Geoboard App that can be used on the iPhone and iPad. There is also a Web App that can be used on computers and with SmartBoards.
The Geoboard is a tool for exploring a variety of mathematical topics introduced in the elementary and middle grades. Learners stretch bands around pegs to form line segments and polygons and make discoveries about perimeter, area, angles, congruence, fractions, and more. You can find more information and download the apps here http://catalog.mathlearningcenter.org/apps/geoboard
There are several YouTube Videos showing how to use the Geoboard App
Overview from The Math Learning Center
Polygons on the Geoboard
Multiplying fractions on the Geoboard
Fraction Relationships on the Geopboard
All of these activities can be done with a regular Geoboard.