Geosearcher is a simple, free app which allows you to enter some coordinates to a location and get the distance and direction to the location. If you are using an iPhone 3GS or iPhone 4, it will also give you your current heading so that you can follow the line more easily.
For instance, are you looking for a geocache? Store the coordinates in the list of saved coordinates and load it up when you get to where youre headed. Then, follow the heading and distance straight to the destination!
This app will always be free, so please feel free to use it however you like!