I am developing an iphone/ipad app to connect with other devices through Bluetooth using GameKit, it works fine with iphone/ipad/iPod but it does not work with other platform devices like android or other Bluetooth devices?
Is there any other framework or code available which could connect to other devices through bluetooth.
No - Gamekit is only for iOS devices If you want to connect to other devices then it should be over standard Bluetooth profiles which both the iOS device and the other device supports
If you are developing accessories that need to connect to iOS devices and want to use your own communication mechanism then you need to join the Apple MFi program and develop accessories as per the MFi program.