I recently ran into a few problems installing XML::Simple on my linux box (mandrake 8.2). You currently can't install XML::Simple without XML::Parser.

Anyway, here's what you'll need to get it done:

1. Install Expat XML Parser, download here: http://sourceforge.net/project/showfiles.php?group_id=10127
   I advise installing from the source rather than using the RPM, as it didn't work for me.
2. Install XML::Parser
   XML::Simple currently doesn't work with out XML::Parser. I just installed through the CPAN shell, no problems after installing expat.
3. Install XML::Simple
   Also, installed easily through the CPAN shell.

Without installing expat, I could not install XML::(anything).

Updated Jan 31, 2003

I recently rebuilt the box with Mandrake 9.0, it was 8.0. Have the same problems with expat and XML::Simple & XML::Parser not installing with the expat RPMS.
I tried both the current release of expat (1.95.6) and the one from the Mandrake ISO (1.95.2); with NEITHER of the RPMS, will either of the mentioned XML modules install properly. Though if I install the (1.95.6) from source, both modules install fine.

Not sure if it is a Mandrake thing or what. I'm pretty sure I haven't been smoking too much crack though.