Apparently Japanese (/Navajo?, anyone know more?) actor Tadanobu Asano has been cast as Thor's pal Hogun, one of the "Warriors Three." Alongside Stuart Townsend.
Idris Elba (best known to US audiences as Stringer Bell from The Wire) is allegedly going to play Heimdall, guardian of the Bifrost Bridge in the new Thor movie. Article here.
Note: The link now goes to a Reuters page instead of whatever godawful blog I linked to the first time without reading the comments there. Sorry about that...