To use PEAR::DB or the PHP database functions

All, I've always used MySQL databases and the MySQL functions in PHP for my code in the past. However, I'm now working on a project that I want the project to be able to be database independent so that the user of the project can use whatever database he/she wishes. I'm looking primarily at providing support for MySQL, PostgreSQL, Oracle, & SQL Server databases. What's the general consensus on how to handle this? Do I need to look at using PEAR::DB so that the type of database is "hidden" from my code or would I look at writing different include files for each database type and each of the include files use the relevant PHP functions? Or some other totally different way? Thanks Dave Merritt dave.merritt@arvinmeritor.com