A civil servant and a former MP's researcher have denied making "damaging disclosures" by leaking a secret memo.
The memo is said to have detailed comments by the US president
David Keogh, 49, and Leo O'Connor, 42, denied three charges under the Official Secrets Act and were given conditional bail. They will face trial in October.
The charges relate to a memo allegedly detailing a conversation between Prime Minister Tony Blair and George Bush.
The White House has dismissed claims that Mr Bush discussed in it bombing al-Jazeera TV's studios in Qatar.
The White House has said claims Mr Bush considered such a move against the Arabic TV station are "outlandish".
Cabinet Office communications officer Mr Keogh denies two charges of making a "damaging disclosure" of part of a government document in his possession as a Crown servant without lawful authority.
Mr O'Connor denies one charge of making a damaging disclosure of a document passed to him illegally.
Mr Keogh is accused of passing a document to Mr O'Connor, 42, who used to work for the one-time Labour Northampton South MP Anthony Clarke, in 2004.
The pair will return to the Old Bailey for another hearing before the trial judge in July. The trial itself is set for 9 October.