How is that different from the Pentagon Papers?
I think the main difference is that Daniel Ellsberg was a member of the US establishment (Defense, MIT, RAND, Marines, Harvard) and Julian Assange is an Australian. And all charges against Ellsberg were dismissed after the court deemed there was evidence of “gross governmental misconduct.” ref
@Graham Cobb: ‘The crimes he is charged with are not publishing the papers (that is very clearly permitted under the US constitution -- and not restricted in any way to "journalists"). The crimes he is charged with are to do with the way he received the information. How is that different from the Pentagon Papers?’
It isn't a crime to receive ‘secret’ files, except in GB-land and the provider has signed the Official Secrets Act. But to be pedantic about, once a file is on the Internet, then it isn't a secret anymore. ref
Who really should be prosecuted is whoever designed a secure communications system, that anyone could walk in off the street and copy all the secrets to a writable DVD.