We at Tigase have just released Tigase IoT Framework for Raspberry Pi.
It's an open source Java framework which supplements Tigase IoT Hub, also Java software. It is part of the Tigase IoT One Cloud package. The framework supports many sensors and devices out of the box and has a good API to easily extend it with support for more sensors. What's interesting, support for new sensors can be written in either Java or Python.
Part of the framework is XMPP client which allows to send sensor data to other clients.
Check it out and let us know what you think.