While there is plenty of software around for the Z39.50 protocol - Zeta Perl doesn't seem to be available for download anymore (it may be because Indexdata who provide the 'Yaz' toolkit for Z39.50 is also unavailable - but it could just be a horrible coincidence). I have seen Net::Z3950 available via ZZPerl, but I couldn't get it working on my Windows2000 development box.