SysInternals.com guru Mark Russinovich has a detailed investigation of a rootkit from Sony Music. The rootkit introduces several security holes into the system that could be exploited by others, such as hiding any executable file that starts with '$sys$'. Russinovich also identifies several programming bugs in the method it uses to hook system calls, and chronicles the painful steps he had to take to 'exorcise the daemon' from his system.
Please write your MP to ensure that they realize that it is Sony and other music distributors that are the ones "cracking" security and breaking into computers, and not people who are circumventing DRM in order to protect their rights (property, privacy, etc).
See also: p2pnet: New: Sony BMG rootkit DRM, The Register: Removing Sony's CD 'rootkit' kills Windows, CNET News.com: Sony CD protection sparks security concerns, PCPro: Sony DRM burrows into rootkit code, BetaNews: Sony to Help Remove its DRM Rootkit, BBC: Sony slated over anti-piracy CD