If you only have longitude and latitude coordinates and want to know where you are, check out PlacesByCoord for Windows Mobile Pocket PC. Version 1.0 is now available for $10.00 USD. You punch in the coordinates and get back the name of the location.
PlacesByCoord covers 193 countries and 300 islands and allows you to enter your coordinate data using a text file (if you have lots of them!).
Source: msmobiles.com