If you were using Pure Perl modules yes, however you may want to use modules which aren't. Find a link to some nice slides here, which demonstrate application packaging and maintanence in detail (N.B. PAR::WebStart and repositories).

My perl app already works on OS X, various Linux distros (from say Centos 3.9 to new), Solaris and AIX. I did that by sticking to pure-perl stuff.

The problem I have now is a new requirement of https support.

Crypt::SSLeay appears dependent on openssl being already preinstalled.

Will PAR allow me to include a compatible version of openssl and whatever else Crypt::SSLeay needs? And also whatever else openssl etc needs?

I've used pp before and have had problems getting it to work across different machines. Which was why I went to "pure-perl" in the first place. Maybe I was just doing stuff wrong.

"I've used pp before and have had problems getting it to work across different machines."

See the FAQ:

"It is not possible to create stand-alone binaries for different platform than what you are currently running on. This is a generally hard problem since you would have to cross-compile all XS modules and perl itself."

You could check which platform the application was running and require additional PAR packages, again see the slides I mentioned, PAR::WebStart, repositories and do some research/basic experiments. It shouldn't take to long for a proof of concept test.