in reply to Are there any major Perl issues with Mac OS X Lion?
The only additional advice I have to offer is to use Perlbrew for managing your personal Perls once you have Developer Tools installed. I've gotten into a habit of not trusting system Perl on any machine. This habit has served me well, and Perlbrew gives me fine-grained control over which version of Perl to run for a given project.
If you're curious about OSX-specific libraries, Cocoa is most likely to be the magic CPAN word. I have not tried any of these myself, since most of my Perl time is command line and Web.