This is the sensor I used for current monitoring for the battery monitoring boards:
http://www.gmw.com/magnetic_sensors/...csa/CSA-1.html
Pretty easy to use, though I'm not sure I like the accuracy. Benefit is that it is easy to change the sensor's range.
Allegro sells some internal hall effect current sensors.
http://www.allegromicro.com/en/Produ...rentsensor.asp