Popstrip was made by Flatwhatson.

PSP homebrew developer, flatwhatson, passed by our forums today to tell us about the release of his nifty app, popstrip v0.3. 
What this baby does is extract PSX ISOs from PBPs. 
According to the dev himself, this version supports all PBPs generated by popstation which includes compressed and uncompressed PBPs from the latest and even previous version of popstation.
Bear in mind that if you don't give a specific name for the extracted ISO, this app will default to "the-name-of-the-PBP.iso". So for example, you try to extract the ISO of a PBP calles popstrip.exe EBOOT.PBP, the name of your extracted ISO will be EBOOT.iso. 

Got it? 

Also, the extracted ISO should be identical to the original used, including the correct filesize.
The dev provided the binaries for win32, linux, Mac OS X, and a win32 GUI. 
He also released the source code for those who would want to tinker with it. Download links are down there, have fun and don't hesitate to ask questions.