Apple may have slipped up and given the first public confirmation of the long-rumored touch-screen iPod. In a PDF document intended for developers discussing the iPod notes feature, the Cupertino, Calif. company references such a device.

In a section titled "Advanced Uses of Notes," Apple tells developers: "Linking to photos and videos is supported only for 5th generation iPods running iPod Software version 1.2 or later. All other Notes feature capabilities described in this document are supported for iPod models with display screens, beginning with the touch-screen models."

According to Apple rumor site ThinkSecret, the next-generation iPod has been in development for over a year and a half. The device will sport a 3.5-inch display, according to its sources. If true, and ThinkSecret's early 2007 date is correct, it would be the first major upgrade to the iPod platform in over a year.

Apple so far has refused to respond publicly, saying it does not comment on future product plans or speculation. However, from its past history, watchers of the company expect it to make some type of iPod announcement at the Macworld 2007 conference in San Francisco.