mapdo

MaPdo is a plug-in which frees WordPress(c) from its database dependency
on Mysql DBMS.

It uses PDO API to interface with various databases, staying as much as
possible off the way of WordPress inner workings, mapping queries on-the-fly
just in time where needed.

The plugin has been built for the purpose of allowing the use of WordPress(c)
with the PostGreSql DBMS, but mappers can be easily written for all the
other databases supported by the PHP5 PDO API.