The PlayStation network has been shutdown since April 20 2011. They are working round the clock rebuilding and strengthening the system and should have it back up within a week, Early May 2011. The related question will have the latest information that has been provided and will be updated as new information becomes available see related question.
It means you have put in wrong redeem codes on psn and can't try again until 24 hours
You should contact the people that run PSN, and ask them what's wrong. I hope this helped in the tiniest bit. ~Rainbowman
No, a Japanese PSN account can only be funded with a Japanese PSN card, one with a yen amount on it.
It's actually known as a PSN ID. http://www.us.playstation.com/PSN/mediago
WHAT DOES PSN STAND FOR OR MEAN
by PSN you need a account to PSN
The PSP-3000 can access the PSN, yes.
You can't. PSN stands for PlayStation Network. You can't connect a DS to PSN.
No you can't, PSN cards are country and currency locked. You cannot redeem German PSN topup cards on a UK PSN account.
No, PSN is free and there is no indication that is going to change.
Yes, there is a PSN link on the Vita's LiveArea.
The password is whatever you set it as when you registered your PSN account.