3G Watchdog. Guarding you against costly Internet overages. 3G Watchdog data counter monitors your Mobile Internet (3G/Edge/GPRS) data usage, shows a status icon (green/orange/red) in the notif bar and a detailed report page. Widget (2 sizes)
Droid Wifi Analyzer - Analyze WiFi with your phone
This app shows information about in-range access points. choose from multiple views to see current network performances. This app is also a Wifi manager, you can see access points list and connect to them.
Show and Analyze the wi-fi channels around you