The first thing that caught my eye about this Ubisoft announcement is that fact that we are no longer calling it Heroes of Might & Magic, but Might & Magic Heroes. Now add the Roman numeral VI and we're good to go. The second thing was the press announcement stating that the franchise is twenty years old--the Might & Magic one, that is. Odd to think I've been around with it since just plain ol' Might & Magic II (and kinda wish they would return to that series--with a decent game).
Regardless, the new Heroes game is being developed by Black Hole, who are said to be enhancing the RPG elements of the traditional model of gameplay. Plotwise, this takes place 400 years before V, and features an angel general set on resurrecting an old war. You take control of the destiny of the Griffin dynasty.
As for features? What's been announced is basically in line with the older games in the series. Grid-based battle map, resources, cities, large maps to explore, and competitive play with other gamers. You can also post content to their hub, which sounds like customized maps, most likely.
The game is set to release in 2011, and I imagine is primarily a PC release. The official website has a vague teaser with an angel, as well as more screenshots, if you'd like to peruse.