This is an example of how the Garmin units will display Custom POI's (Points-of-Interest). In this example, each of the entries were built from individual .GPX files. If we click (well, lightly press actually!) on "StonePages", the next screen opens to reveal the individual entries from the .gpx file.
Each one of these entries is a single 'Waypoint' that has been created or amended using GeePeeEx Editor. If we 'click' "Tregeseal Stone Circ(le)" the details for that waypoint will be displayed.
These details were entered into the Address and Phone number fields. Notice that "Phone:" prefix has been automatically added. If this was a Bluetooth enabled unit, this would be replaced by an Icon, which you could press to actually dial the number. Since I added a description as well, the a "More" button has been displayed. This behaviour varies amongst units. The image on the left is from a StreetPilot C510; that on the right from a Nüvi 310.
To view the description, we press "More", or scroll down, depending on the unit. In this instance, it is some background information about the location. (Cut and Paste from Wikipedia, straight into GeePeeEx Editor).
We're not quite finished yet though. If you notice, there is an "Image" button. Clicking this, will display our final screen, which is a picture of the location, so we know what to expect when we get there. On the Nüvi range, a small thumbnail is displayed, which will show the full image when 'pressed'.
This image and the text above are from Wikipedia.
This test-file is available for download - have fun creating your own!