The units require little setup to be usefull, but offer plenty of changeable user fields on various pages to assist in provinding more valuable info. You are best to play around with these yourself, or ask someone. You could also load additional maps (with more details), a favourite seems to be the free Shonkymaps .
Now the fun part is to be able to download your flight. This is great to show fellow pilots or friends, to analysis your flight, or to simply remincess.
The basic SW supplied from Garmin (MapSource) is quite good and is also usefull for backing up & managing waypoints. This has a neat feature of linking directly to Google Earth.
If you want to look at your flights over a real surface you need Google Earth . To view in Google Earth you will need to create either a Google Earth (.kml or .kmz) or a (.gpx) type file first. Or download from Garmin MapSource and use the direct link (as listed above).
If you would like to download your flights to one of the online XC comps you will need a .igc type file. A recommended program GpsDump