The Kylix 2 dbExpress PostgreSQL/RedHat Database driver is now available as a registration incentive download. You can download it from the Kylix 2 registered users website once you have registered your Kylix 2 product.
If you received your copy of Kylix 2 before the registration site was live and have already started using Kylix, you can follow the instructions at http://www.borland.com/kylix/webreg/ to register.
Enjoy.