Every time I read the words "web service" stuck together, the alarms in my head goes on like crazy; if there's an ill defined, over hyped phrase nowadays is probably that one.
Perl can do most Java can do without sweating, however things are less formalized than in the Java world.
As for the beast itself, Perl has a superb support for databases (DBI) and LDAP directories; and fantastic building pachake(s) like HTML::Mason and an decent support for XML protocols like SOAP or XML-RPC (loads lighter that SOAP) if you can allow its limitations.
If you know Perl, take the advice given by a fellow monk in this trhead (I forgot who, sorry). If you happen to know Python, Zope can be another (free software) possibility to construct the thing (dunno much about it myself).