If you're not familiar with geocaching, it's a location-based hobby where you seek caches (usually small containers with a logbook and goodies inside) based on hints, latitude and longitude coordinates, and a keen eye. You can also hide caches for others to find. GroundSpeak has a free Geocaching Intro app available if you're interested in learning about the hobby but don't want to make the $10 investment in the full app.
So what's new in Geocaching v.4? A lot. The user interface has been redesigned to make it much more streamlined. I found that actions that formerly took a number of screen taps are now usually no more than one or two taps away. Although I'm not fond of long lists of features, there's no other way to show all of the additions and improvements:
-- Google Maps integration (now have choice of Google Maps, Bing, or OpenStreetMap)
-- Ability to take photos and submit them with geocache logs
-- Ability to submit logs for trackable items such as geocoins and travel bugs
-- A logs tab with displays of pending and sent logs
-- Better reliability downloading pocket queries
-- Online / offline indicator
-- GPS acquisition status and location display
-- Listen to iPod app during caching
-- Support for home location (specified in geocaching.com user profile)
-- Notepad for every geocache listing
-- View any list of caches on map
-- View trackables inventory
Geocaching 4 has not been specifically rewritten for iOS 4 or the iPhone 4, so if you want to see the map graphics in all of their glory on your Retina Display, you're out of luck. A few screenshots of the revised app are included in the gallery below.