I figured for those of you who dont want to risk bricking, I would write a little guide to help you experience the awesomeness of this sweet program. Here it is:

First download the original copy of the program located here: http://dl.qj.net/CIntro-PSP-Homebrew-Applications/pg/12/fid/10679/catid/140

Ok the original instructions call for the modification of the config.txt located in the SYSTEM folder. This used to be used for the custom firmwares like 1.5, but not the 3.00 and above ones. So instead,

    * copy the INTRO folder found in the .rar file you download and put it into the SYSTEM folder in your psp's memory stick. 

    * Now you need to copy the same folder to whatever folder you have defaulted for running 1.5 kernal (for me this is simply the GAME folder but you need to consult ur recovery mode to see what yours is).

    * Next you need to rename the folder that u copied to GAME (or whatever) to BOOT and then open it and delete the "intro" file (this is not nessasary and basically taking up space).

    * Now that this is done, go to your SYSTEM folder and open up the INTRO folder that u just copied there. You will see the exact same files as the one you placed in the GAME folder. This is where you place your .pmf file that you want to use for the coldboot movie. Rename it "intro" and overwrite the current one. Now the hardpart is over.

    * Cold start your psp and enter recovery mode. You need to enable auto run program.

And thats about it. Now everytime you cold boot your psp, youll see ur sweet movie and you can change it freely and even remove it without writing to the flash! 

--Shadowz
http://forums.qj.net/showpost.php?p=1318246&postcount=1