"Now is the time for the established democracies to give tangible political, economic, and security assistance to the world's newest democracy," Bush is to say in a speech on Monday.
Excerpts of the speech were made public by the White House.
The 2003 Iraq war sparked a serious split between Washington and a group of European countries led by heavyweights France and Germany opposed to the conflict.
EU foreign ministers meeting in Brussels on Monday are set to agree to help train Iraqi judges, police officers and prison wardens in a gesture of goodwill a day before a summit between European and US leaders on Tuesday.
Although the final details have yet to be hammered out, 700 to 800 Iraqis could participate in the programme, diplomats said.
The EU ministerial agreement will come before summit talks on Tuesday between Bush and his Nato and European Union counterparts.