BridgeChecker for Mac OS X
Coming to the App Store!
BridgeChecker is a utility that can automatically disable/enable wireless interfaces. Whenever your computer is connected to an Ethernet port and the link state is good, the utility can automatically turns off the IEEE 802.11 wireless network interface. This conserves IP address allocation, reduces security risks, resolves dual interface routing issues, and prolongs battery life.
BridgeChecker on Mac App Store
Below are screen shots of app user interface on a MacBook Air.
BridgeChecker Settings Window
BridgeChecker Active Wireless Interface Status
BridgeChecker Active Wired Interface Status