I just tried your plugin with Wordpress 2.9 (and PostgreSQL 8.3). Really nice. It works well for me. Though there were some small fixes to add :
- deal with socket connection to Postgres;
- fake mysql_version was to old;
- index names need to be table name suffixed to avoid name collision
- on duplicate key do not exist within PostgreSQL, used a RULE for wp_options instead
- REGEXP must be replace by ~

I did a diff, here is the link : http://www.mariel.fr/docs/driver_pgsql.diff

WordPress database error ERROR: syntax error at or near “15″\nLINE 1: …ts WHERE DATE_SUB(‘2009-11-05 11:18:03′, INTERVAL 15 DAY) > …\n

Thanks again for great plugin!

Juergen