This was posted on Paul McCartney's website on May 1:
Website security statement
Following the statement, which appeared on this site on the 10th of April 2009, we have investigated further into the security breach/hacking incident on the paulmccartney.com website between the 4th to the 6th of April inclusive. As soon as we became aware of the security breach we disabled it and since then have been working with our technical experts and the relevant law enforcement agencies so as to minimise any impact.
No personal details of any users visiting the paulmccartney.com website were/are held on the server hosting the site.
We recommend that all users who visited the site between the 4th to the 6th of April inclusive carry out their own computer virus checks, by using an up-to-date virus checker, to ensure that their computer has not been infected with any malicious software. Users should be vigilant and be aware that hackers may use malicious software to obtain personal information from the user's computer and may use such information to open accounts and/or purchase goods; accordingly, users should check their bank accounts and personal statements frequently.
If a user discovers that their computer has been infected or that any personal information has been compromised they should alert their credit card companies and banks immediately.
www.paulmccartney.com
(Note: Our column containing the earlier statement is here.)