The best defense of Wikileaks that I've read is by Simon Jenkins in yesterday's Guardian:
Anything said or done in the name of democracy is, prima facie, of public interest. When that democracy purports to be "world policeman" – an assumption that runs ghostlike through these cables – that interest is global.
Governments at all levels seem to have completely forgotten this.
Wikileaks asked the US govt for a list of people who might be put at risk by release of the documents -- the US, typically high-handed, refused to answer. Jenkins writes:
It is for governments, not journalists, to protect public secrets. Were there some overriding national jeopardy in revealing them, greater restraint might be in order. There is no such overriding jeopardy, except from the policies themselves as revealed. Where it is doing the right thing, a great power should be robust against embarrassment.