Apple’s success with iTunes has finally attracted the attention of the virus writers, according to security firm Trend Micro.

A new worm, WORM_OPANKI.Y, is circulating online. It poses as an iTunes file and is spread using AIM (AOL Instant Messenger). While it does not affect Mac users, it does attack most breeds of Windows.

The virus poses as a file named "iTunes.exe" in an attempt to trick users "into thinking that this worm is associated with a legitimate product," Trend Micro warned.

When activated the worm sends a message to all online contacts of an affected user, which reads, "this picture never gets old". Each message has a link to a URL where users download a file that appears to be a Jpeg.

At the same time, the software will begin to download spyware and pop-ups when activated. It also tracks internet sites infected users visit.

Trend Micro warned: "This worm has backdoor capabilities. It opens a random TCP port and connects to the IRC (Internet Relay Chat) server Once connected, it joins the IRC channel fate, where it listens for commands from a remote malicious user. It then executes these commands locally on affected machines."

It's not a major threat and, according to the security firm it hasn’t yet spread too widely.