1) "Get Perl going" on your server using the ActiveState Perl 5.8.X release:
http://www.activestate.com/Products/ActivePerl/?psbx=1

2) Get the mod_perl.so built for your Apache Windows distribution and install (following their instructions).

3) Enable the module in your httpd.conf:
# Add to your httpd.conf
LoadModule perl_module modules/mod_perl.so

---

Other help:
http://perl.apache.org/docs/2.0/os/win32/install.html
http://perl.apache.org/docs/2.0/os/win32/config.html
http://oceanpark.com/notes/howto_redhat8-apache2-mod_perl.html