Yes. The cast has signed on for two additional films, and the first sequel, Thor: The Dark World, was released on November 13, 2013.
What other mentions of the Marvel characters are there?
(1) Erik tells Jane and Darcy of a fellow scientist he once knew who studied gamma rays and who came into contact by SHIELD who then went missing shortly afterwards. If this is a set up for The Avengers movie then its likely he is referring to Bruce Banner, The Hulk, although others speculate it could be Hank Pym or Betty Ross but neither of them are in The Avengers movie. Also, both Erik and Banner will be in The Avengers movie and so could have a 'reunion' scene. (2) The special SHIELD agent at the crater site with the bow and arrow who has Thor in his sights is Clint Barton, AKA Hawkeye. (3) The big, strongly-built black agent who fights with Thor in the scene previously mentioned could be Luke Cage, or a reference to this character. (4) When the Destroyer first appears and is surrounded by the SHIELD agents, one SHIELD agent asks Agent Coulsen, "Is that one of Stark's?" to which he replies, "I dunno. That guy never tells me anything." They are of course referring to Tony Stark, AKA Iron Man. (5) Nick Fury appears in the post credits sequence.
Who and what is the significance of the S.H.I.E.L.D. agent with the bow and arrow who has Thor in his sights?
Clint 'Hawkeye' Barton (Jeremy Renner) joins the Avengers in The Avengers (2012).