I saw on Adam Leventhal's blog that Apple ship a DTrace provider for Perl with Leopard:
"Not only did Apple port DTrace, but they've also included a bunch of USDT providers. Perl, Python, Ruby -- they all ship in Leopard with built-in DTrace probes that allow developers to observe function calls, object allocation, and other points of interest from the perspective of that dynamic language."
It's also mentioned on Unix Technology page for Leopard.
I had a quick look to see if Apple had released any patches. I didn't find any -- at some point I should dig around their open source section, to see if it's included in that.
I did find OpenSolaris Bug ID 6355891 asking for Perl support to be added to DTrace.