Apple recently sent a "cease and desist" email to bluwiki demanding the removal of postings by users who are trying to figure out how to write software that can sync media to the latest versions of the iPhone and iPod touch.
According to the EFF: Apple doesn't have a DMCA leg to stand on.
At the heart of this is the iTunesDB file, the index that the iPod operating system uses to keep track of what playable media is on the device. Unless an application can write new data to this file, it won't be able to "sync" music or other content to an iPod. The iTunesDB file has never been encrypted and is relatively well understood. In iPods released after September 2007, however, Apple introduced a checksum hash to make it difficult for applications other than iTunes to write new data to the iTunesDB file, thereby hindering an iPod owner's ability to use alternative software (like gtkpod, Winamp, or Songbird) to manage the files on her iPod.