Map view - supporting Open Street Maps and Open Cycle Maps by default, configurable for other map types, including google maps.
GPS view - shows the distance and direction to the selected geocache.
Cache details - once a geocache is downloaded, all necessary details are available even in offline mode.
Paperless geocaching features - take notes for a geocache on the go, see the hints and spoiler images, check the latest logs.
Fieldnotes support - Ever came home after a long tour and wondered which of those geocaches you found? Never again: Log your find in the field and upload notes and log text when you're at home. Review them on the geocaching website and post the logs.
Multicache calculation help - Let your phone do the math for you. Working for the most multi-stage geocaches, AGTL finds the coordinate calculations (like "N49 (A+B)2.(B*2)(C/3+4)1") and lets you enter the missing variables. After the solution is complete, it's a matter of two clicks to set the result as the next target.
Advanced waypoint handling - AGTL finds waypoints in the geocache descriptions, in the list of waypoints and even in your notes. For your convenience, they're displayed on the map as well - see where you have to go next.
Sun compass - Nobody needs a digital magnetic compass (which the N900 is lacking) if he/she has the sun as a reference point :-)
And last but not least:
In active development
AGTL is available on the N900. The latest stable version can be downloaded via this link (on your N900). The latest development version is available in the extras-devel repository.
One of the coolest features in the new AGTL is the automated detection, parsing and resolving of formulas in multi-caches. AGTL allows the user to input missing variable values and calculates the resulting coordinate. The user is being warned if AGTL suspects a wrong value (see screenshots).
My software is not under the Beerware license, but you can buy me a beer anyway.