I test the DIY Drones magnetometer ( HMC5843 magnetometer breakout board ) using Happy Killmore's Ground Control Station connected using SERIAL_UDB_EXTRA telemetry format, to a UAV DevBoard V3 running MatrixPilot (revision 729 of trunk).
photos:
http://picasaweb.google.com/peter.hollands/Twinstar2Build#5547623052830239122
UAVDevBoard / MatrixPilot:
http://code.google.com/p/gentlenav/wiki/Home?tm=6
HK GCS:
http://code.google.com/p/happykillmore-gcs/
DIY Drones Store:
http://store.diydrones.com/HMC5843_Triple_Axis_Magnetometer_p/br-hmc5843-01.htm
Self Calibrating Mathematics, and software to integrate via I2c written by William Premerlani:-
http://diydrones.com/profile/WilliamPremerlani
Source Code:
http://code.google.com/p/gentlenav/source/browse/trunk/libUDB/magneto_udb.c