When dealing with OS X, I was advised by experienced Mac users to install perl (and unix stuff in general) from the MacPorts (http://www.macports.org/). It went all very well, I only encountered a few gotchas resulting from perl not being located in its default destination:

• You have to change the shebang in perl scripts, the trick is to use #!/usr/bin/env perl
• You have to specify PATH in your crontabs