The first serious geocaching application I've seen on the Appstore - and it looks good. It does *not* display any navigation aids as such (i.e. a compass rose or similar) but read the FAQ for why this is not included (one reason is that the author has not mastered the graphics on the iPhone well enough - so 10 points for honesty!)

The iGeocacher is a small application that allows me (and you) to parse the data in a set of geocaching files in .loc or .gpx format and then display them via a web application in the safari browser on your iPhone. The lat/lon coordinates are coupled to the Google maps function so that you just touch the icon or link on the desired target and you'll see it depicted on Google maps. Just touch the directions button and get detailed driving instructions to your waypoint

[From iGeocacher]