I'm John Reyst, the original creator of d20pfsrd.com, the largest Pathfinder Roleplaying Game SRD (System Reference Document) site.
I've started setting one up for MnM (3E) using the Open Game Content portions of the rules. I want this site to support and promote the Mutants and Masterminds game as d20pfsrd.com does for the Pathfinder game, by getting more people into the system by letting them see the system before they buy.
Anyway, the site can be found at http://www.d20herosrd.com. It's not 100% complete yet but it's coming along nicely. I've gotten permission from Storn Cook (artist of many Champions art pieces) to include some of his art on the site also.
I'd love to hear any comments pro or con about the site. You can email me at firstname.lastname@example.org if you've got any thoughts!
Thanks and good gaming all!