While Microsoft's Zune may have briefly toppled Apple's iPod from the top of the Amazon.com bestseller's list, US customers are having a hard time getting hold of the new version of the product.

Amazon briefly showed the last-generation Zune as its best-selling MP3 player earlier this week. Essentially it appears that a steep price discount on the superseded product had inspired bargain-conscious US shoppers to buy one of Zune's so-called 'iPod-killers'.

While that report attracted lots of publicity, it did ignore that Apple had no less than 15 slots in the top 25 list - Microsoft clearly has some way to go to regain lost ground in digital media.

Now the Zune 80, the Apple competitor's top-of-the-range Zune player is already sold out and in limited supply across US retail outlets. The 80GB device includes WiFi and an FM radio, but was pretty much unavailable - just in time for Thanksgiving, which took place yesterday.

Despite strong sales, it's not Apple that Microsoft is killing, but its previously jilted 'Plays For Sure' partners the company is hurting most.

From Apple's standpoint, even if demand for Zunes is strong, it would likely take share from other hopefuls, not Apple, Shannon Cross, analyst at Cross Research told USA Today. "No one is going to touch" Apple, she said.