preseed_package.pp:

define preseed_package ( $ensure ) {
   file { "/var/local/preseed/$name.preseed":
     source  => "puppet://$server/files/preseeds/$name.preseed",
     mode    => 600,
     backup  => false,
     require => File["/var/local/preseed"]
   }

   package { "$name":
     ensure       => $ensure,
     require      => File["/var/local/preseed/$name.preseed"],
     responsefile => "/var/local/preseed/$name.preseed",
   }
}

portion of manifest with java:

   preseed_package {
      "sun-java6-bin": ensure => "present";
      "sun-java6-jdk": ensure => "present";
      "sun-java6-jre": ensure => "present";
   }