For those of you with a Droid(and probably all Android OS phones), Blackberry or to a lesser extent an iPhone(because of it's shitty AT&Tnetwork) there is a program out there that turns it into a tracker like the SPOT. The SPOT sends a message every 10 minutes and there is a $100 yearly charge. The instamapper(http://www.instamapper.com/) uses the cell network and is free. The downside is you have to have cell coverage for this to work so as you descend into mountain strips it will lose the ability to send it's position. My experience with Verizon has been that even over some pretty remote areas the phone shows a signal, good enough to send and receive text messages, therefore the instamapper will work. Your mileage will vary depending on your carrier. Where the SPOT only sends a message every 10 minutes this new program sends a message at whatever time interval you set, the default is every 10 seconds. I have set mine to every 3 minutes for now. The more often it sends the more battery it uses. Where the SPOT's first generation unit would miss 10-20% of the position reports and therefore leave gaps on the map this program allows you to set the number of points it keeps in memory if it misses a scheduled check in, I have mine set to keep the last 25 in memory. The new SPOT always sends the current position and the last three, I believe. The SPOT never knows if it's reports get thru, this program knows as it's a two way system. As people follow you online they see your position on a Google map, your heading, groundspeed and altitude. Like all Google maps you can show street maps, terrain or satellite maps. So far it is superior to SPOT and after more testing if it continues to be that way I'll cancel the subscription on the SPOT and just use it for emergencies. In the flights I have made and then checked there hasn't been one missed report.
By the way, nice write up on the SPOT in this months AOPA Pilot about a guy in a 206 who crashed in Idaho last summer, as well as the mention about the guy on this board who crashed and the SPOT went thru the windshield and he had to go find it while injured.