Update: The index is defunct. It was only hosted on perlmonk.org, which now seems to be down for the count. Please disregard the below. My regrets to all.
Since the PMSI - Perl Monks Snippets Index is gone for good, here's a new Snippets Index.
It appears that the original PMSI simply listed the snippets ordered by different fields — title, author, date.
Of those, the only one that seems remotely useful is ordering by title. If you want snippets by a given author, Super Search lets you find them; and ordering by date is practically useless. Hence, the following index, which orders only by title. (But also see Snippets Permuted Index.)
What people could really use is a catalog of snippets with value-added fields such as domain, complexity, quality. That would be a good collaborative project. ;-)