Hm! Groundspeak (at www.geocaching.com) is announcing a geocaching application on their site - the feature set soudns a lot like iGeoCacher:

Groundspeak’s Geocaching Application will provide real-time, direct access to Geocaching.com’s database of worldwide geocaches. Application features include: access to geocache details, including description, hint and recent logs, trackable item lookups, and full navigation capability.
Watch this space for additional information, coming soon.

[From Geocaching - The Official Global GPS Cache Hunt Site ]