iBodger is a free mobile application for creating Warmachine and Hordes army lists, and managing your collection. The last version was 4.1, and is current through January 2012. There will be no more updates.
Privateer Press will soon be releasing an official mobile app, War Room, with full card stats, damage tracking, and more.
iPhone, iPod Touch, iPad
Download iBodger 4.1 for iPhone on the App Store.
Android
Download iBodger 4.1.1 for Android from Android Market or here.