I'd suggest that before buying a book, your friend should find out a little about perl first. There are a dozen online tutorials that would help him get his feet wet writing simple cgi's (try a search on perl tutorial). I know for me, a beginning programmer, I should have looked into Java before rushing out to buy a book and then deciding I didn't really like the language very much. When I decided to learn perl I knew better. I checked it out via a few tutorials first, decided I really liked it's capabilities and (maybe as importantly) it's 'design philosophy' for lack of a better term, and then went out and bought "Learning Perl on Win32 Systems".
That's what worked best for me.
Your results may vary.