The Stop the War Coalition said 100,000 people had signed the petition stating that Mr Bush was not welcome in Britain and should not have been invited.
Mr Kovic - a Vietnam veteran whose story inspired the Hollywood film Born on the 4th of July, starring Tom Cruise - said they wanted to send the message to Mr Bush and Mr Blair that the war was "misguided and wrong".
"What is happening in Iraq is a mirror image of the nightmare that happened in Vietnam. This is unacceptable and we will not stand for it," said Mr Kovic, who is wheelchair-bound as a result of his war injuries.
"What we are doing with the petition is essentially making a statement to President Bush that this war is terribly wrong. It is terribly misguided. It must end. This war was misconceived from the start."
Mr Kovic was joined by the MP for Glasgow Kelvin, George Galloway, who was expelled from the Labour party over his outspoken opposition to the war, and the Labour left-winger Jeremy Corbyn.
still time time to cancel??