I realize this is an old thread, but I thought I'd jot some notes. The Android Bluetooth example (already listed) has a bunch of issues (not the least of which is you need 2 Android devices to get it to function).
Take a look at the example at http://luugiathuy.com/2011/02/android-java-bluetooth/
where he is using BlueTooth on the Android device to hit a server (to do some robotics work).
Be aware of UUID issues (the way that BlueTooth decides what connection it can make is defined in the UUID), and check out
http://www.avetana-gmbh.de/avetana-gmbh/produkte/doc/javax/bluetooth/UUID.html
Keep in mind that the 16 bits represented in the UUID (ie, 0x1101 for Serial Port) is misleading in that its really the least significant part and needs to be coded 0x00001101.
