For recent versions, if you try to run Perl programs from the command line via file-association, it will throw away your command line arguments. To fix this, copy-n-paste this bit into a .reg file, and double-click to import it.
Actually, that didn't work for me, I had to use this instead:
Windows Registry Editor Version 5.00
@="\"C:\\strawberry\\perl\\bin\\perl.exe\" \"%1\" %*"
The easy way to make .pl files executable without the .pl extension is the pl2bat program.