How can a CC company know if the transaction is fraud or legit, if some haxor dude pays a plane ticket with my CC details how will they know if it is fraud?
Surely it isn't as simple as me filling in a form and I get refunded?
My bank even stops me paying for £20 of food loads of times at Tesco so it's seems like everything is fraud to them

Not sure i'd agree with that, there will be huge numbers of people with a PS3 who may have added card details etc. who won't necessarily read gaming sites or forums, email would be far more effective at getting news to those sorts of customers.
It would have been good if they added the announcement on the message you get when you try to log in on the PS3 and on the site as well.
I've heard that all personnel details including credit cards may have been obtained and I want to change my password but do I do it on the main website still?
Yea, but you can't log in at the moment.