An engagingly written (yes really!) whitepaper on Microsoft Rights Management including Azure RMS. I’d recommend reading the whole thing, but otherwise the licensing information starts on page 14. Three key takeaways: no licences are required for consuming rights protected content (only if you’re doing the protecting), Office 365 E3 and E4 already include Azure RMS (these suites are said to be “RMS-enlightened”), the Azure RMS subscription will be available as an add-on subscription both through MOSA and the EA (looks like September 2013). Get the whitepaper here: http://bit.ly/1cacWIJ.