You activate the Map mode by tapping on MENU > MODES and then picking "Map".
By default, native Google street maps are used and here is just a short list of what you can do with the map:
Free and full versions.
Full version only.
More information on maps:
Maps video tutorial (full screen, offline and custom)
Some of features described are available only in the full version. You can upgrade by tapping here.
All modes: Default mode • Waypoints monitor (e.g. speed cameras) • Rally computer • Taximeter • Map • Heads up speed display • Full screen speed display • Full screen map display • G Force acceleration monitor • Land navigation mode • Idle timer and alert mode • Water sports boat mode