Nice work there. Are you going to open source the code that's accessing the PSN service (at least partially), or are you offering access to your web service only? Your source code page says "coming soon".

It's probably not that bad using your web service for "public" information (where one just has to enter the PSN ID without password), but you have to understand that I don't want to use my PSN password on the web service, and I don't think it's a good idea for users of the app as well.

Things that require a password (I assume that's the friends list) should access the Sony servers directly from the client without sending login credentials to a third party webservice. AFAIK there could be credit card data stored in a PSN account in the list of recent purchases, so it's really a security/trust issue.