Apple set devotees and the Internet abuzz with a trademark minimalist invitation to a press event in downtown San Francisco.
The email invitation sent late last week says "Let's Rock" and contains a brightly colored silhouette of a person leaping enthusiastically while listening to an iPod.
The only other information given is the time the press conference starts and directions to the theater where it is taking place.
"The best bet is they are going to refresh the iPod Touch and the iPod Nano," said analyst Rob Enderle of Enderle Group in Silicon Valley.
Enderle and others tracking the market expect Apple to raise iPod Touch technology to the level of the iconic California company's iPhones, offering all capabilities except mobile telephone service.
Apple is expected to switch the shape of its Nano models back to slim gum sticks from the squat design it tried in order to feature a small screen for video viewing.
Speculation preceding the event includes the possibilities that Apple will announce another software patch to fix connectivity problems with its new iPhone 3G models.
Analysts are also wondering whether Apple will also announce new versions of Macintosh laptop or iMac computers.
There have been reports of shortages of iMacs, and Apple is known to let supplies of devices clear out of warehouses and stores before introducing new models.
Microsoft is also evidently anticipating Apple plans to invigorate its iPod line for the year-end holiday shopping season.
A day ahead of the Apple press event, the US technology giant announced a revamped line of Zune MP3 players and software upgrades that make listening to music on the devices even more "social."
The Zune line-up is being expanded to include devices with 16 gigabytes of flash memory selling for 200 dollars each and a 250 dollar model with a hard drive offering 120 gigabytes of memory space,
Free software updates will let people instantly buy songs they hear on the devices' built-in FM radios and wirelessly download music from the Zune Marketplace without having to connect to computers.
"We've always known that radio is the primary source for discovering new music," said Clear Channel Radio chief executive John Hogan.
"Microsoft's decision to marry music discovery and delivery does two things: enables consumers to instantly satisfy their passion and enables FM song tagging to be enjoyed by all radio listeners, everywhere."
Microsoft software will also let Zune users customize radio "channels" that pick songs based on their tastes. Zune software will also enable listing to audio books.
Zune users will have the option of buying songs individually or paying 15 dollars monthly for "Zune Pass" subscriptions allowing them to download or stream as much music as they wish.
The new Zune models and features will begin rolling out on September 16, almost two years after Microsoft launched the devices in November of 2006.
"Zune has been on the market a while and it is about time for Microsoft to refresh that line," Enderle said.