I've released any::feature. (It will take a while to appear on CPAN; look at the development repo on github.) It can be used like Perl 5.10's 'feature' pragma and will try to "do the right thing", regardless of whether you use Perl 5.8 or Perl 5.10.
So far it's a proof-of-concept and will only handle the 'say' feature.
Read about it in my blog.