There is a detailed preview of Heroes Kingdoms at Multiplayer Online Games Directory that explains how the Heroes series expanded to the Web. Screenshots are included to show some of the most common interface screens.

"Empire sims are one of the most prevalent genres when it comes to free-to-play MMOs. In a lot of cases, most of them play exactly the same, with the only difference being a new coat of paint and a few different rule changes. Besides being based in the popular Might & Magic mythology, Might & Magic: Heroes Kingdoms also succeeds by approaching the genre in a fresh way."

But unlike what the article says, the game is already available in North America. You can start playing here.