VirtualGPS - is a free, small utility, which fully emulates GPS receiver and returns your location (by using cellular towers and wifi hotspots). Location accuracy is about 50-500m.

TUTORIAL
1. Run VirtualGPS, wait less than 1 minute until GPS: ON (or OFF in bad case) will be shown.
2. Run navigation software. In the settings put GPS on COMx (Port is displayed on the main screen).