In the open letter to Prime Minister, Julia Gillard, the authors express "grave concerns" for Julian Assange's wellbeing and their "believe that Julian Assange is entitled to all protections enshrined in the rule of law - and that the Australian Government has an obligation to ensure he receives them."
It is no secret that the debate about Wikileaks is heated, and that calls to "punish" the whistleblower seem to be louder than calls to ensure that his fundamental rights (including the right to a free and fair trial) are respected. I wouldn't join the debate at this point, but I would say that the right to freedom of expression is a fundamental right and governments have an obligation under international law to recognize and uphold this dwindling right. It is the responsibility of States to ensure that "confidential" information is not leaked. In an event where such information filters out, governments should refrain from cracking down on private individuals who make the information public.
At the moment, Julian Assange is under arrest on charges unrelated to Wikileaks. Legal action against Assange in relation to the publication of documents would be similar to the arrest of journalists in Ivory Coast for publishing a corruption report in July 2010.
Before you take sides or jump into hasty conclusions, find time to read Q&A about Wikileaks and Freedom of Expression, and Wikileaks and Internet Freedom.