Trackapult is a useful little utility for iOS and Mac, which allows you to sync the current playback position of any song between your devices.
Comet allows Meteor billpay users to view their remaining minutes, sms, and data on a simple, clean user-interface.
EirText is an app for iPhone, iPod touch, & iPad, which allows you to send free or cheap text messages.
EirText for Mac is an app for Mac OS X, which allows you to send free or cheap text messages.