I’ve found that the GPS in the iPhone is surprisingly good. Here’s a quick tutorial on geocaching with the iPhone 3G.
Step 1. Navigate to the geocaching.com website and choose a cache.
Step 2. Scroll down and click the “Google Maps” option under the “For online maps…” section.
Step 3. The cache location will open in the Google Maps application.
Step 4. Click on the GPS targeting icon in the lower left hand corner. This will move the map to your current location once a GPS lock has been established. In this image I’ve switched to hybrid map mode.
Step 5. Since the cache I was seeking wasn’t that far away, I simply zoomed out on the map and walked toward the pin. Alternatively, you could click on the pin location and use the “Get Directions” feature if driving will be required.
Step 6. Walk toward the pin, zooming the map in as appropriate.
Step 7. Once the cache is within the pulsing blue ring, start looking. The marker in this image put me about 25 feet from the cache. Not too shabby.
Step 8. Log the cache while you are at ground zero and can inspect the contents and container. You can be very accurate in your maintenance reports by doing this. After that, sit back and enjoy the view.