Apple has issued a warning shot to companies hoping to use its iTunes music software as a selling point with a new notice on the company's support pages.

"Apple is aware that some third-parties claim that their digital media players are able to sync with Apple software. However, Apple does not provide support for, or test for compatibility with, non-Apple digital media players and, because software changes over time, newer versions of Apple’s iTunes software may no longer provide syncing functionality with non-Apple digital media players", the statement reads.

The move, which is clearly aimed at Palm's recent public push to let prospective users know that they can use iTunes to sync their music to the new Palm Pre, could affect future syncing options if Apple decides to make an aggressive move to block such third-party digital media players.

But it's not just the Palm Pre handset, which is yet to launch in the UK, that allows users to connect to iTunes. Other manufacturers, including BlackBerry and MP3 player maker Creative, have used the power and appeal of Apple's music software application to sell their multimedia credentials and allow people to switch away from Apple.

It is not clear at this stage if Apple plans to do anything more than idle threats or warnings at this time.

We will keep you posted.