Yes it is
You can sign up to the PlayStation Network by going into "PlayStation Network" on the XMB, then click 'Sign Up to PlayStation Network'. Or you can follow this link to sign up on your computer, then transferring your account to your PlayStation 3 console. http://www.us.playstation.com/PSN/SignUp
Get an Xbox.
The network is down more information is available at related question
In order to connect to the Playstation store you must sign in to the Playstation Network and select the icon from the Xmb for the Playstation Store.
you sign up and it's free on a psp
You have to be 18
yes to play on the PlayStation network you need to sign in That allows them to ban people who break the rules
There is an option on the xmb menu, under the playstation network section, that says sign up :)
As soon as you are on the profile that you activated Auto sign in, it will log in to the PlayStation Network automatically for you
Follow the steps on the related link
Yes if you are able to sign in to the Playstation Network and your WiFi is cable or DSL broadband
PlayStation Network is the main service that PlayStation uses for all of its online services, such as online multiplayer. You are connected to PlayStation Network whenever you sign-in, or play a game online. You can also access the PlayStation Store on PlayStation Network, as well.