No apps can do a better job in analyzing Wifi Signal other than Wifi Analyzer. It is similar to the Android apps, and you can also say that it is similar to a Windows based Inssider. Once install, you will be able to visually check WiFi signal strength, radio channel, the MAC address of the AP.

Check on SSID

SSID Strength

It used to be in the App Store, but not until Apple take it down.

Since the latest update of iOS 5.0.x, the old Wifi Analyzer (from App Store) can’t work anymore, it is related to the different API needed in iOS 5 to detect WiFi signal as oppose to iOS 4.x. The latest version that supported iOS 5.0.x has been released in Cydia, but that of course for the jailbroken Iphone. It will cost you 1.99USD


Wifi-Analyzer in Cydia