MSSQL::DBlib & MSSQL::Sqllib - Two Perl classes for accessing Microsoft SQL Server from Perl from MS Windows only. - http://www.sommarskog.se/mssql/
DBI.pm - A Perl module used for the connection, retrieval and storage of data from various database applications. - http://www1.uni-hamburg.de/RRZ/Software/DBI.pm/DBI.pm.html
DBD::MySQL - Basic abstraction layer for working with databases in Perl, a driver for using MySQL with DBI and a pure-Perl implementation of the MySQL client-server protocol. - http://dev.mysql.com/downloads/dbi.html
Survey of DBI Wrappers - Reviews and tabulates the features for many of the DBI wrapper modules available on CPAN. - http://search.cpan.org/dist/DBIx-SQLEngine/SQLEngine/Docs/Related.pod
The Poop Scoop - A review of the various modules available for Perl Object-Oriented Persistence (POOP), including RDBMS-OO mappers. - http://poop.sourceforge.net/
Butler.pm - A Perl module that enables Perl scripts to access the Butler SQL database. Currently, this only works on Macs, so this will only be useful with MacPerl. - http://remus.rutgers.edu/~petechen/Butler/Butlerpm.html
Class::DBI - Provides a convenient abstraction layer to a database. - http://www.class-dbi.com/
DBIWrapper - Designed to facilitate easier access to databases using DBI. High level methods for reading, writing, committing and rolling back transactions are provided. - http://dbiwrapper.sourceforge.net/
DBIx::Browse - Designed to facilitate the browsing (INSERT, UPDATE and DELETE) of related database tables. With demonstration. - http://dbix-browse.sourceforge.net/
DBIx::Password - Allows creation of a global password file for DB passwords. - http://tangent.org/index.pl?node_id=420
libsite-db-perl - Provides basic and easy database-connectivity through both URLs and standard DBD-parameters. - http://freshmeat.net/projects/libsite-db-perl/?topic_id=68%2C90%2C45%2C910
CPAN: Database Interfaces - Listing of modules and their corresponding documentation. - http://search.cpan.org/modlist/Database_Interfaces