Before you fill up your car, check if you potentially can be skimmed: Skimmer Scanner – Android Apps on Google Play
The app is open source at sparkfunX/Skimmer_Scanner: A mobile app for detecting bluetooth gas pump credit card skimmers.
A long article about reverse engineering these skimmers is at [WayBack] Gas Pump Skimmers – learn.sparkfun.com including tools to get the data out: [WayBack] MPLAB PICkit 3 – PGM-09973 – SparkFun Electronics
All via: [WayBack] Gas pump skimmers – what you need to knowIf you’re on android, there’s an app that essentially finds and pairs with the skimmer to see if it’s active… – Lars Fosdal – Google+
–jeroen
I think it’s Jan Wildeboer that referred me to the 
