http://playstation.joystiq.com/2009/02/25/dave-perry-absolutely-certain-next-psp-will-forego-umd/

http://www.gamedaily.com/articles/news/david-perry-certain-sony-working-on-umdless-psp-2/?biz=1

http://www.engadget.com/2009/02/26/psp-2-is-ready-and-umd-less-claims-earthworm-jim-developer/