HornetQ will support AMQP in one of the next versions.

I am still wondering if there is any plan of supporting MQTT.

http://en.wikipedia.org/wiki/Mqtt

http://mqtt.org/faq

http://mqtt.org/software

http://www.eclipse.org/paho/

http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html

If not, would it make sense to support this in HornetQ?