Taoiseach Brian Cowen and British Prime Minister Gordon Brown are launching a deal to save the North's power-sharing government - confirming it will take on policing and justice powers from April 12.
The deal between the Democratic Unionist Party and Sinn Fein includes new plans on overseeing parades.
The deal comes after nearly two weeks of round-the-clock negotiations and brings an end to fears that the power-sharing government could have collapsed on the policing, justice and parades stand-off.
A six-member working group is to be established to deal with controversial loyal order parades. Its work will begin immediately and will be completed within three weeks.
The deal envisages local people providing local solutions which respect the rights of those who parade as well as nationalist residents.
Mr Brown praised the settlement, saying: "The achievements have been as great as they are inspirational.
"This moment and this agreement belongs to the people of Northern Ireland, all of the people, and now more than ever before so does their future. This is the last chapter of a long and troubled story and the beginning of a new chapter after decades of violence, years of talks, weeks of stalemate."
The North's First Minister Peter Robinson welcomed the deal and said: "There are some who will play politics with this agreement but the real focus in the months to come must be on building an administration at Stormont that our whole community identifies with and supports."
Deputy First Minister Martin McGuinness said that as an Irish republican he wanted to see a united Ireland but recognised that unionists preferred to maintain links with Britain. He insisted both communities could and should live together in mutual respect.
Mr Cowen added that the deal laid the foundations for a new future.