text: Al-Sadr Loyalists Agree to Hand Over Arms BAGHDAD, Iraq - Shiite militiamen loyal to radical cleric Muqtada al-Sadr agreed Saturday to begin handing in weapons, a significant step toward restoring order in Baghdad's sprawling Sadr City slum as the interim government struggles to curb Iraq's more widespread Sunni insurgency.    In a sign of persistent Sunni unrest, clashes flared in several cities as the search continued for the body of British hostage Kenneth Bigley, who was decapitated by his abductors - reportedly after a failed escape attempt...