OE-A, OE-B and Popstation Guide
DCEmu has posted a pretty through guide on how to install Dark_Alex's Custom Firmware OE-A, upgrade to OE-B, and run PSOne games using Popstation. You can get these files in the Firmware Hacks and Launchers section of my homebrew software library. If you're confused about how to go about doing all of this and would like to know how, then check out the guide over at DCEmu using the link below.
DCEmu OE-A, OE-B, Popstation GuideVia DCEmu