Rumor has it that the latest firmware updates for the PSP and PS3 have allowed playing of all PSOne discs on the Playstation Portable via the PS3 using remote play.
I haven't been able to check PSOne disc based games, because I can't find a single one, but we do have readers reporting in that they work on the system via Remote Play. In a bit of unwarranted exuberance I decided to see if any PS2 games would play via Remote Play, and the answer remains no. I did test out some PSOne games I had downloaded from the Playstation Store and they all seemed to work fine.
Another neat feature I noticed is that you can now assign which buttons do what on your PSP while in Remote Play meaning Lair should finally work if you want to play it remotely... and still own it.
Comment here if you can get your PSOne discs to work via Remote Play. We've contacted SCEA for comment, but haven't heard back from them.