what do the klingons look like?

[sithious]

as i live in europe i haven't so far been able to see more of the new star trek series than the trailer ... (anyone know where the episode may be downloaded?)
my main question therefore:
what do the klingons look like?
are they like in tng and ds9 and voyager or are they like in classic ... just guys with beards, no prosthetic forehead or anything? i wonder how this change in looks is going to be explained...

 

[Red Phoenix]

They have the bumps on their forehead in Enterprise. There was an episode of DS9 where they went back to the Tribble episode (for reasons I can't remember). Dax or someone else asked Worf why the Klingons had no bumps then, and all he said was, "We don't like to talk about it", or something like that. So personally, I just blame it on mass temporary genetic insanity.