Instructions
Open a Web browser such as Internet Explorer or Firefox.
Copy the following Web address or click the link directly in the "Resources" section: http://us.PlayStation.com/publictrophy/index.htm?onlinename=psnidhere. To copy, highlight the text, right-click and click "Copy."
Right-click the address bar, click "Paste" and press the "Enter" key. Replace the "psnidhere" at the end of the web address with the PSN ID you want to check for availability. If the ID is available, a "No User Profile" message will appear onscreen.