WASHINGTON — When Apple said it was going to make an announcement at San Francisco's Moscone Center this week, it triggered another elaborate guessing game.

Could it be the iPhone Nano, the subject of speculation in a financial analyst's report this summer? What about a WiFi-enabled iPod that some bloggers are buzzing about?

C'mon, Steve Jobs, how about a hint? No, Apple remains tight-lipped.

If documents prepared by an Apple partner and obtained by The Washington Post are to be believed, both of those products are in the works and slated for release in the coming months. One would be an iPod with WiFi and a touch screen like that on the iPhone; the other would be an iPhone Nano with less storage capacity and a lower price than the $500 iPhone.

Such speculation not only moves markets, it also prompts action from companies, from retailers to analysts and accessory makers, for whom every Apple launch creates new business opportunities.

A J.P. Morgan analyst in Taiwan scrutinized patent applications and probed overseas vendors, concluding in a July report that an iPhone Nano — a version smaller in size and capacity than the iPhone launched in June — would be released this year.

The report caused such a stir, another J.P Morgan analyst issued a subsequent report clarifying the firm's position. "We have been unable to independently confirm ... so we are not yet convinced this is a likely event" before year's end, the analyst, Bill Shope, wrote.

There are other clues bloggers are trying to imbue with significance. One is that Apple's retail channels apparently have not received new iPod inventory in recent weeks, a possible sign that a new iPod will come sooner, rather than later, bloggers said.

In the end, everyone is just making educated guesses. But they're also making a few bucks for Apple investors. It's fun to get excited about a new gadget, but, alas, there is a potential downside for Apple, said Rob Enderle, principal analyst with Silicon Valley's Enderle Group.

"If it brings out a product that doesn't capture the excitement ... I wonder if people will be disappointed because it doesn't come up to the levels of what's expected," Enderle said.

Apple declined to comment on the nature of tomorrow's announcement, and Kasper Jade, publisher of the AppleInsider blog, isn't surprised.

"Obviously, it's Apple's job to keep a tight lid on things," he said. But it's his job to try to uncover the news, so he talks regularly with retailers, many of whom are also in the dark on Apple's plans, he said.

Some of the biggest sellers, including Circuit City, Best Buy and Wal-Mart, declined comment.

"It kind of goes both ways with the retailers," Jade said. "We talk to them about what's going on, how the inventories are doing. They give us status updates. We share information we have."