Check out this great introduction to MQLight and BlueMix by the experts!
Introducing, @j0nnymac, Mark Walters, Charlie Martin and Mark Phillips - development gurus in the world of Cloud Messaging, as you have never seen them before!
Why not have a play with BlueMix for free? https://ace.ng.bluemix.net/
And download and play with MQLight for free too : https://developer.ibm.com/messaging/mq-light/