Heading using a Magnetometer and Accelerometer

In any navigation project, it's important for us to determine the heading at any given time. Our weapon of choice is an LSM303DLM magnetometer and accelerometer module. Pololu has provided the libraries for use with the Arduino. It includes all the necessary functions for us to determine heading, so minimal work needs to be done.
We're experiencing drift between power cycles, so self tests will probably be done on power up for best accuracy. Aside from that, the data readings appear to have very little noise and is rather consistent. The next few steps are to calibrate the readings so all directions read correspond to the physical orientation and to integrate it with the rest of the ROV/AUV. Based on rough readings and a traditional compass, the headings are quite accurate.

The libraries can be found here:
LSM303DLM