Here is the Actual Prime donwload Link for Alpha 1:
http://dl.qj.net/psp/homebrew-games/prime-psp-alpha-1.html
Here is the Engine source. I am working on getting it updated. Because of My laptop failure, I have to get the engine back to how it was. So if you are going to just play Prime, Don't use this eboot.pbp [Updated 9/8/10]
http://www.mediafire.com/?vtwh7c1f8725xmn
Here is Primes Qc. It is close to being up-to-date with the Alpha. Updated [9/8/10]
http://www.mediafire.com/?6ubhphvdkg3km4r
Good luck With Prime and your Personal Mod!