This is Red Squirrel's most recent multi-disc PopStation program for Windows (as of 4/3/2008). This program is a GUI used for converting one OR multiple PlayStation One (PSX) disc images into PSP format.
This program is available from many sources on the internet, but without a few crucial .dll files. This torrent includes the full software, documentation, and the normally-missing files, cygwin1.dll and cygz.dll, taken from a previous version of PopStationMD (2.0).
Need more help using the program to make PSX games that are playable on PSP? Google is your friend. ;)