My PC is running on windows but my web host is unix, I'm hoping theirs a method I can kill both birds with a single stone.

Yep, fork, which incidentally is fork() and not FORK(), is now emulated under Windows.

C:\temp>perl -le "print fork"
-5720
0
[download]

Taking this very cutdown script, can someone show me a very simple fix to add fork() to this? Everything inside the loop is what I'd aim for, to make the page crawling a multi-process.

I would either use piped opens as a cheap solution in that case, or rather than reinventing the wheel while risking do so the wrong way, I would use a dedicated module like Parallel::ForkManager or the even more specific LWP::Parallel (and related modules).