(The other Sony customer using Linux on PS3s, against Sony policy, is the Air Force, whose "Condor Cluster" supercomputer depends on Linux and on direct access to the PS3's GPU. Sony was kind enough to give it special permission to keep using the Linux kernel for the 2,016 PS3s the Air Force had already bought.)
The accusation and justification for the April 5 attack Anonymous posted on its public-information site is still there, but so is a follow-up from April 6 saying Anonymous had cut off the DDOS attack because it was hurting Sony customers more than Sony itself.
There's also a wry announcement from April 22 averring that "For Once We Didn't Do It."
There is a link to the CNET story warning of a third attack. The only response from Anonymi, who normally flock and argue about any big project even while conducting it, the only comments by mid-morning Eastern time were "[WTF] is that?" from one Anonymous, and "Can anonymous stop the hackers?" from another.
Sony may be attacked this weekend, but it's unlikely to come from Anonymous – at least not from the bulk of it.
Rather than a penetration attempt or DDOS attack, Sony could be suffering a different kind of social-engineering exploit – one that uses the resentment poor treatment has built up in its user base as an echo chamber in which to raise unsubstantiated fear of more attacks, prompting even more defensive measures from Sony, and even more public Sony bashing from its customers.
At this point it may not be necessary to mount any kind of credible attack at all to spook Sony. All it may take is sneaking up behind it and yelling 'Boo!'