RAMDroid

RAMDroid is widget that shows amount of unused memory of your Android device.

RAMDroid is an open-source lightweight widget to show how much unused RAM your device has. You can add it to your homescreen, and then once you tap the widget icon it show the available memory size right within the icon.
You can download at: http://apk.cuaban.net/detail/7804/ RAMDroid .html