Congressional negotiators agreed yesterday on an “Amber Alert” child kidnapping law that is now expected to be enacted this week. The law will stiffen maximum sentences on child kidnappers and child pornographers. It will create a national child kidnapping notification network named after Amber Hagerman, a 9-year-old Texas girl who ws abducted and killed. The legislation authorizes federal matching grants to states and communities for equipment and training for a network that will distribute information via broadcasts and electronic highway signs about kidnapped children. The law includes child pornography provisions in response to a Supreme Court ruling that voided an earlier law.