Information here, and new information here (should be good news for the hardcore folks).

Highlights:

Some of the original peeps from Fallout, Fallout 2 and the canceled Van Buren are running this project.

Hardcore mode gives ammo weight, requires drinking water, and doesn't allow instant healing.

Ah, I loved Fallout 3 -- at first I thought New Vegas was an add-on instead of a whole new project (why not call it Fallout 4?). Anyways, yeah, this could be really cool. Looking forward to it.

I can see the reasoning behind it; they don't want people to think it's just a sequel... it takes place on the other side of the country, and it's linked to the first two storywise, but not the third. That and you don't play the part of a vault dweller.