Hi Lionclaw1
There was a lad who's not been on the forum for a while, Luis who was into the PSP version of lemmings, I think he has created levels, not too sure if it was new PSP levels or just the normal lemmings levels. Have a look around, I think Flopsy is right about the online community for the Psp lemmings.
I quite liked the psp version of lemmings, back in the day that was one of my main reason for buying a psp was to play the lemmings and the worms open warfare.