The internal column name for the Created column is the author.
Write an ItemEventReceiver element and override the ItemUpdated method:
public override void ItemUpdated(SPItemEventProperties properties) {
SPSecurity.RunWithElevatedPrivileges(delegate
{
using (SPWeb web = properties.OpenWeb())
{
web.AllowUnsafeUpdates = true;
SPUser spUser = web.EnsureUser("USER_NAME");
string strUserId = spUser.ID + ";#" + spUser.Name;
spListItem["Author"] = strUserId;
spListItem.Update();
}
});
}
EDIT: ; .