Planetbeing from the Dev-Team has just released an application on the Cydia store called Signal. The app gives you a breakdown of all the nearby cell towers and their signal strength, and is useful (especially for unlocked users) to see which carrier actually has the best coverage in your area. The app works on every iPhone (except the 2g-only original) in any country.
Signal is a Cydia Store app I wrote for jailbroken iPhone 4, 3G, and 3GS that shows you interesting data about your cell reception as well as plots a map of your nearby cell towers. Compare coverage between different carriers, test antenna vulnerabilities on your phone, or determine your nearest cell tower. Radio engineers will also find being able to see the downlink and uplink frequencies and scrambling codes of neighboring cells useful for field testing.
The app isn’t exactly cheap at $5, but if you think of it as a donation to the wonderful Dev-Team, it’s a small price to pay for all the freedom they have brought to your iDevices. The next version even has a “Death Grip Game” to see if you can replicate the antenna problems ‘scientifically’. Search for “Signal” on the Cydia store to buy this helpful utility.