PSN ID Linking FAQ
It appears as though that the official PlayStation forums (us.playstation.com) has started linking PSN ID's to your forum user/login ID.
Lets hope they add trophy support as well as a "gamercard"
What is the PLAYSTATION®Network?
The free service from PlayStation® that allows you access to Online Gaming and the PLAYSTATION®Store. It also gives you a variety of ways to communicate with your friends.
What if I don't have a PLAYSTATION®Network ID?
It's not a problem; register your online ID today!
Why would I link my PLAYSTATION®Network IDs?
Once you've linked your IDs, you'll receive all these great features:
o Identify yourself on the Web using your PLAYSTATION®Network portable ID
o Display your PLAYSTATION®Network portable ID on social networking sites
o Meet other PLAYSTATION®Network members
o See who's who on the PlayStation message boards
o Keep tabs on your PLAYSTATION®Network friends on the Web with the Friend List
You can also view your PSN friends list from the official playstation forums.