JMS 2 is arguably one of the most important parts of Java EE 7. The JMS 2 EG officially published it's Public Review Draft today. Characteristic to the great work JMS 2 spec lead Nigel Deakin always seems to pull off, he created a pretty detailed page for the Public Review Draft on the Java.net project for JMS 2.
Nigel invites you to read the draft/Javadocs, download the reference implementation (standalone or with GlassFish), take the JMS 2 example code for a spin and send either him or the EG your feedback. The page also neatly summarizes the actual changes in JMS 2. The formal review period began on January 3rd and ends on February 4th, so act now!