Well I saw him shed a tear and it released the hammer and gave him life and his powers back..I figured Odin was able to resurrect him with magic or whatever.
__________________ Don't play games with me General
Thor did die.But because of his self sacrifice, it made him worthy again of Mjolnir.Hence Mjolnir suddenly going to where Thor was.And the scene were Odin was speaking, is a flash back shown of the words he uttered.Wasn't the movie about "Whosoever holds this hammer, if he be worthy, shall possess the power of Thor." statement after all?