Ostia 6 did show you what your co-ordinates are. But mapping software or plain co-ordinates won't help you find a cache. For Geocaching this is what I use. I'm sure there's other programs like it.
http://vitotechnology.com/en/products/navigatorii.html
I dock my axim to my computer, and turn on remote display. Then I go to
http://www.geocaching.com and add all the waypoints I'm gonna look for.
Then off I go. You really can't judge where you are going just by looking at the co-ordinates. And what good is a street map when you're on a park trail. You want a compass, and a directional pointer. These hiking programs have those. You just have to get used to the fact they update while your walking/moving.
It shouldn't matter what GPS unit you have either. But I've found the Pharos one is off a little bit on cloudy days.