Google Scholar Citations lets you track citations to your publications, check who is citing your publications, graph your citations over time, compute citation metrics, and view publications by colleagues.
HearPlanet is a real-time audio tour guide. This application plays audio tracks of Wikipedia articles based on points of interest surrounding your current location. Compatible with iPhone and iPod Touch.
Nature.com reader apps allow you to read scientific content on the iPhone, iPad, or iPod Touch. You may browse news and free open access content, save material to read for later, save searches, and access the articles' references.