MPs are due to vote on whether British troops should join in the fighting if war does break out on Thursday.
The vote will take place on Tuesday night.
It's a crucial time for Prime Minister Tony Blair, who backs the war, as three members of his team have already resigned over the Iraq crisis.
The Iraqi leadership quickly rejected this request on a TV station owned by one of Saddam's own sons.
But the White House has now said it will move forces into Iraq even if Saddam did back down, to hunt for weapons of mass destruction.
People in Iraq are stocking up on water and food supplies, and some shops are closing, as war looks more and more likely.
Three people have already the quit the government in protest. They are: