We just released a fully featured version of our popular free app No Signal Alert. No Signal Alert Pro is now in the market for $0.99 and it comes with some really cool features, here's a short description and screenshots of our app.
No Signal Alert detects when your phone is in a "dead zone" or with zero bars and sends a customized alert of your choice (sound, vibrate, led, etc).
* Customize your alert
* Map view of your dead zones
* Signal statistics
* Supports GSM and CDMA