Apps
From Rhizomatica Wiki
Android Apps for GSM signal analysis
GSM Field Test [1]Logs signal strength and geolocation viewable live as a big fat line of dots on a google map. Logs are downloadable as kml files.
Shows GSM dBm or WIFI strength on a meter and shows info on cell tower locations, your IMSI and other details about your phone and network. Also logs info downloadable as kml files.
RF Signal Tracker[3]Another RF signal app
Web based tools
Open Cell ID [4]
GSM Signal strength heatmaps, base station locations, API and Android app.