The Society of Professional Journalists first issued this code in 1973 to provide guidelines for responsible reporting. It is followed by journalists with integrity. www.spj.org/ethicscode.asp
From the spj.org website:
The SPJ Code of Ethics is a statement of abiding principles supported by explanations and position papers that address changing journalistic practices. It is not a set of rules, rather a guide that encourages all who engage in journalism to take responsibility for the information they provide, regardless of medium. The code should be read as a whole; individual principles should not be taken out of context. It is not, nor can it be under the First Amendment, legally enforceable.
For an expanded explanation, please follow this link.