after what seems like 2842 revisions I finished my GPS datalogging shield. Logging GPS & sensor data to a DOS-formatted SD card is basically at the very edge of the Arduino's capabilities but it -does- work. The design might be useful for people doing geo-locative art, surveying-style projects or just want to build their own datalogger. Theres also example code for putting the Arduino into deep-sleep for x seconds which may come in handy.
Im currently doing run-time power tests & will have precise numbers soon.http://ladyada.net/make/gpsshield/index.html