After some time of geocaching I found that if I am close to cache I need compass for precious looking for the cache. I tried to make electronic compass module for my Treo650.
After it worked successfully I wondered if there is any way how to use it with CacheNav plugin for CacheMate. I tried to ask author of CacheNav if he could incorporate this functionality into CacheNav - but I got no reply. I did little bit of reverse-engineering work and wrote small patch for CacheNav to support Compass inside CacheNav.
Both Compass application and modified Cachenav you can download here.