Native Applications
If you are wanting to develop your own applications, or port existing ones, this article on Installing Apps may be a useful introduction. We also have an OpenPeak Apps List of official applications.
PnP III
This is multi-app installer which will quickly set up a Joggler with the following apps, games and tools:
Opera Mobile 10.1 browser, Outlook.com, Gmail, Yahoo Mail and Twitter shortcuts (via Opera to the mobile versions of the sites), The Lounge Internet Radio (allowing customisation of stations via a little fiddling/file editing), Logitech Media Server installed with BBC iPlayer radio add-ons installed, the ability to make Network Shares available using a web interface and access them via LMS, Squeezeplay, BBC iPlayer featuring live and on demand viewing of TV and radio, YouTube (customisation possible with a little fiddling/file editing), UPnP (Connect and Play) - Play Shared Media with no further tweaking, Google Calendar, RSS News reader (customisable with a little fiddling/file editing), AccuWeather app, Timer and Stopwatch, Calculator, Facebook app, Flickr app, Dilbert cartoon, Lots of simple flash games including Angry Birds, Google Maps, GTalk (has GTalk messaging functionality), Music, Video and Photos, Memos, Horoscopes, SWF Launcher including Reboot and Shutdown scripts to save pulling the plug, Alarm, Screen Off one-touch icon, Mount Writable USB shortcut, PDF Reader and Squeezelite and required libs for manual launching/tinkering