Okay guys, I just went through this in General Discussion, but here it is again. Duddie and Tratax were the original and AFAIK the only aothors of PSEMU PRO. It was they that devised the plugin system to allow different plugins to be written and used. Anyway, they had just come out with a beta version of their latest release and they sent out to the beta testers who tested it for them. One of these testers was someone who called himself Strider and he was a personal friend of theirs. They thought they could trust him, but he took it upon himself to leak (give out) the beta copy of PSEMU PRO to the emulation community against their wishes.

This so disgusted and saddened them that they immediately stopped all work on PSEMU PRO, thus killing it. PSEMU PRO was an awesome emulator for it's day, it played many game accurately, w/good sound and in 3d. If it had been continued, one can only imagine where it would be today.
But one good thing did come of this, Diddie gave his permission for the plugin system to be used by other emulators so we are able to have ePSXe and Adripsx today.
There you have it, the story of what happened to PSEMU PRO, sad isn't it?
sincerely,
sx/amiga