Under the bluetooth documentation for Android Developers. There is the Bluetooth Chat application example which will contain an activity for facilitating the communication between two devices, as well as the service connection. This will be your best example for what you are looking to do. Here is the link to the Tutorial, you will also find a link to the BluetoothChat application under here:
http://developer.android.com/guide/topics/connectivity/bluetooth.html
To see the BluetoothChat application you will first need the Android SDKs, and then you will be able to find the source.
Generally, do some research first, as here is another question of the same sort that has a little more detail, and shows the user made a good attempt first.
Bluetooth Examples for Android
After following the BluetoothChat application, or the written tutorial on the Android Docs, if you run into bluetooth errors, and other problems with your code. Stack Overflow is definitely the way to go for receiving quality answers to your troubles!