More exciting news today is the Project PSIO, a project to have a SD Card Adapter for the PS1, heres the details:

Project PlayStation Input Output (pronounced sigh-oh) is a project in development that will allow you to back up your PlayStation CD-ROM's and let you then play them directly off an SD card on the actual PlayStation 1 console.
We have also gone to the trouble of adding a PS1 Development section for the users who would like to program and share their work. This is basically a way of replacing the Yaroze server that Sony shutdown a few years ago, as well as preserving and providing a free and dependent backup of the SDK's, tools, manuals, code and much more that are impossible to now find.
Regards, The PSIO Team.

http://psio.com.au/