Your iPhone tags photos with all sorts of information: your location, the time and date the photo was taken, even exposure information. This tagging function can be turned on or off under Privacy > Location Services in your iPhone settings. Surprisingly, you can't see the tag information on the iPhone itself, but it is available in iPhoto and other applications on a Mac or PC.
Pic Navi (free, ad supported) makes it easy to browse the photos on your iDevice and see each photo with a date and time displayed. Tapping the compass button in the app displays a map of the location where the photo was taken and tapping the pin on the map provides directions to get back to that spot.
Moving between photos is easy. Just swipe left or right and the metadata is displayed automatically.