Deepak Singh of Amazon Web Services maintains a great list of (cloud-focused) parallel computing frameworks and platforms:
<a href="http://deepaksingh.net/Resources/Computing_in_the_Cloud" rel="nofollow">http://deepaksingh.net/Resources/Computing_in_the_Cloud</a><p>He's on twitter, too: <a href="http://twitter.com/mndoci" rel="nofollow">http://twitter.com/mndoci</a>