> To my knowledge, Wikileaks has never actively participated in the hacking or cracking required to access restricted info.
But that's exactly what this is about. There are records of Jabber messages where they were conspiring (planning) to crack the password for Manning. I don't know how they determined that Assange was involved and not an unfortunate pawn of his, but whatever evidence they have was enough to convince a grand jury to indict him.
And, btw, an indictment isn't a verdict. He still has a chance to defend himself in trial even if he's extradicted. But this would mean that the US has a chance to prove his guilt.
But now we just wait and see if they have enough evidence to convince the UK to extradite him. And if that happens we'll wait and see how the trial and sentencing plays out.