Pocket SOTA allows you to carry the Summits on the Air (SOTA) summit database with you on your iPhone or iPad. With the app you can dig into the Associations and Regions worldwide, plot summits on the map, view some SOTA related websites to submit spots, update the database and view all summits in a region.
You can drop a pin on the map and find summits nearby.
You can also export a GPX file from the mapping tools to impot into your GPS, Google Earth, etc.
When viewing a summit's details, you can calculate azimuth and distance to the peak from your current location using GPS.