A trademark Apple special event will be held next week in San Francisco, and it looks like new iPods.
(Credit: Apple)

Apple has sent out invitations for a music-related event next week, and the smart money is on new iPods.

The invitation, titled "Let's Rock," went out Tuesday inviting media to the Yerba Buena Center for the Performing Arts in San Francisco next Tuesday at 10 a.m. PDT. Rumours have been building for weeks that Apple is set to introduce new iPods at what will be its fourth September iPod event in as many years.

We've been expecting Apple to hold a September iPod-related event since March, when audio chipmaker Wolfson informed its shareholders that it had been shut out of the design of next-generation media players from "a major Tier 1 customer" who planned a third-quarter launch. Launching in September gives Apple plenty of time to build distribution and marketing for new iPods ahead of the holiday shopping season, when the company sells the bulk of its iPods for the year.

The most persistent buzz over the past month has circled around a revamped iPod Nano that brings back the long, slim design from earlier generations but provides for a widescreen video display as found on the current generation. That rumour looks even more promising after the discovery of "fourth-generation" iPod Nano cases by Engadget Spain over the weekend that would fit the design laid out by iLounge and Digg's Kevin Rose.

Another likely candidate is a revamped iPod Touch at a new price. The iPod Touch looks set to get the curved outer shell (manufacturing efficiencies) and the cheaper price tag (marketing efficiencies) that came along with the introduction of its sister, the iPhone 3G. And Apple has said that iPod customers responded well to the price cut on the iPod Shuffle, so perhaps it wouldn't be much of a surprise if Apple decides to test how they'll respond to more capacity at the same price point.

What else might be coming? Apple is expected to release OS X 2.1 at some point in September to try to move past the widespread bugs introduced along with the 2.0 release, and next week's event might also deliver a preview of that software. The wireless industry will be in town that week for the CTIA Wireless IT and Entertainment show just a block away from the Yerba Buena Center, and I expect Jobs will take the occasion to release sales numbers for the iPhone 3G.

We expect Apple to introduce new notebooks fairly soon, but it would seem a bit odd to try and cram new notebooks into a major music-related event. The old iTunes music-subscription rumours resurfaced last month, so that's a possibility. And Apple's decision to highlight "rock" gives credence (of sorts) to my goal of predicting an iTunes-Beatles partnership to arrive before every upcoming Apple music event, figuring I'll be right at some point.

More details might trickle out before next week's event, so pay attention. And don't buy an iPod between today and next Tuesday if you're looking for something new.