According to the RabbitMQ docs, the RabbitMQ server is already installed on Debian 6 Squeeze.
rabbitmq-server is included in Debian since 6.0 (squeeze) and in Ubuntu since 9.04.
I tried to start it via SSH and invoke-rc.d rabbitmq-server start but realized that there is no rabbitmq-server in init.d. - rabbitmqctl status also is unknown. I also could not find it with dpkg --get-selections.
I have to admit that I am new to Linux, but could it be possible that there is no rabbitmq server preinstalled? Or maybe I am looking in the wrong places?