ffgriever the creator of ESR released a Public Preview of PS2PSXe, which is a PS1-Emulator for the PS2 and should be able to run PS1-Images from all devices (CD/DVD, HOST/LAN, HDD).
This is the first Homebrew-PS1-Emulator released for the PS2.
This is a Preview-Version and before a Beta-Test-Version is released, bug-reports are of no importance.
Infothread "PS2PSXe - cleaning the house": http://psx-scene.com/forums/showthread.php?t=62387 (PS2PSXe - cleaning the house)
It's not sure yet, if this is compatible to backward-compatible PS3s and it is also not sure, if it ever will be.
Even if it is only a Preview and not a Beta with all the newest coded stuff, I think it is worth a news-post.
Spread the news and share the info.