I had OSX 10.4 installed on my Dell laptop for a while. I liked it a lot, but could never get the video or wireless working with the proper drivers.
That aside, OSX is a *nix based OS with the Mac Windowing system on top of it. It is absolutely sweet as it incorporates a really nice desktop system with the power of Unix. Also, yes, it came with Perl
Due to the *nix nature, I was able to go to www.perl.org and download the source version of Perl, compile and installed it and it ran just fine. I set up the standard CPAN interface and installed modules with ease.
I would personally not recommend Active Perl, but that is just me. I hate their lack of support for all modules.
If you installed Active Perl and when you do Perl -v and it still returns 5.8.8, then the original installation that came with your OS is still active on the system. Try doing a "which perl" on the command line in the Terminal and see what it returns. You may find that it returns something like "/usr/bin/perl" and possibly others. If it does, use the full path to each and find out which are for 5.8.8 and which are for 5.10. If that is the case, the you can simply delete the 5.8.8 binaries and create sym links to the version you installed.
Regards,
Jeff