If you are in/near London, the
Prince Charles Cinema occasionally shows some of his stuff (I've seen Seven Samurai, Yojimbo and Sanjuro there, plus I think they've shown Ran and Kagemusha there too).
You can also get a decent BFI box-set of the samurai films (but sadly there doesn't appear to be one of his more modern stuff like the fantastic High and Low or Stray Dog, you've got to get hold of them individually).