Im a newbie also with an iphone. Was getting frustrated today as tried finding about four different caches and couldnt see them. My iphone seemed a bit indifferent to my needs....
One minute it said 30 metres one way then it 40 metres the opposite way which creates quite a large area to search!
Was going to look in to getting a garmin type device but it sounds like should be ok with the phone, just need to gain a little experience using it.
Also i need to be a bit more patience in the actual search rather than expecting to find it straight away!