http://pc.ign.com/articles/800/800570p1.html
http://www.gamespot.com/pages/gamespace/updates.php?pid=918428&sid=6173397&tag=topslot%3Btitle%3B1&om_act=convert&om_clk=topslot&page=1
http://www.gametrailers.com/player/21125.html
Some key things summed up:
*The game is mainly first-person, but there are several viewpoints to choose from (Much improved from Oblivion). Can be tweaked to resemble the original top-down perspective
*The game world is slightly smaller than Oblivion with less NPCs, but with much more varied and well-defined characters.
*Stats, items and such are all intergrated into the PipBoy on your wrist for a more seamless and immersive feeling.
*20 hit songs from the 40's have been licensed for use in a resurrected radio station with an actual DJ and news about ongoing events in the game. The radio can also be used to pick up isolated frequencies, leading to more quests and such.
*The consequences of your actions will be much harsher, opening up new opportunities while closing others allowing for much more replayability, unlike Oblivion where you could join any factions regardless of what you've done.
*The black humor will still be there, but with less breaking of the fourth wall (IE no blatant Monty Python or Hitchhiker encounters).