I've looked on roll20but didn't find the game listed (supposedly because it isn't grid based). Some are actively recruiting on the Margaret Weiss Productions forums ( and on RPG Geek ( as well as the Google Plus MHR community (https://plus.google.com/communities/113114436417291762579).
In the case of RPG Geek, the people I've seen looking for players are posting in geeklists, especially the 2014 RPG Challenge: Play 5 Games New to You list.
When you're just getting started, it is certainly possible to figure out the game from the books and just start running it for your friends. One great tip I would add: try playing it yourself.
That's how I and others learned to game "back in the day." But there are certainly things that can help. Build a character and roll some dice, even if it's just you and the rule-book.
As with any big project, it's best to take it one step at a time: Fortunately, much of the work of preparation, once done, can be distributed to other educators.
Also, since MHR is Cortex Plus, much of the mechanics are shared with Leverage, Smallville, Firefly, and Dragon Brigade.
Looking at those can shed light on the fuzzier areas of MHR.
Further still, Cam Banks, the designer, is active in the G , RPG Geek, and MWP forums, and often helps people grasp it. I would really love to know why it was cancelled, and even pulled from online stores such as Drive Thru RPG.
He's VERY accessible online, and seems to be a genuinely nice guy. Luckily there seems to still be a very strong player base that makes up for direct support from the publishers.
Like any inquiry-based exercise, role-playing needs to be followed by a debriefing for the students to define what they have learned and to reinforce it.