New day, new geek app in Cydia: Signal. Signal was developed by PlanetBeing from the iPhone DevTeam and maps the cell towers you are connected to and displays detailed cellular information from the baseband.
NOTE: after installing this app, your commcenter must restart, which means you will loose bars for about a minute. NO, it’s not and iPhone 4 design flaw.
You can buy Signal from Cydia Store for $4.99