How can I use digital compass cmps03 with arduino Esplora?

I received a Esplora about a week ago and I've done some simple programs with the sensors included in the board, but now I would like to use it to read a digital compass:

The compass sends a PWM which represents the angle or the angle can be read via I2C. I did this with an arduino duemilanove once and it was easy but I don't really know how to do it with the Esplora. What do you suggest me?