The latest system updates should have added a link to the PS Network Store to the PSP's menu. As long as you log in with an account for the Japanese store, you should be able to get access to it.
Alternatively, you can access it with a PC then use a USB cable to put it onto the PSP. I don't have the PC software, so I'm not sure what you did exactly to access it.
Edit; Here's the link to the PC site:
http://www.jp.playstation.com/store/
Alternatively, you can access it with a PC then use a USB cable to put it onto the PSP. I don't have the PC software, so I'm not sure what you did exactly to access it.
Edit; Here's the link to the PC site:
http://www.jp.playstation.com/store/
Edited: 2008-11-06, 3:26 pm
