use Sub::Name
foreach (keys %news_sites)
{
  *{$_} = subname "generator_for_$_" => sub {...}
}

##</code><code>##

foreach my $key (keys %news_sites) {
   *{$key} = sub {
       ...
       # as the $key variable was declared in the outer scope of the subroutine,
       # if the code reference survives longer than this scope it will retain its
       # value
       warn $key; # this will warn the value used when defining this sub.
   }
}