With all the hand-wringing about consumer spending and the holiday shopping season, at least one technology device appears to be holding its own: Apple’s trusty iPod. In fact, the now ubiquitous music and media player is faring so well that Kaufman Bros. analyst Shaw Wu is beginning to see a shortage.

Wu said stocks of certain iPod models have been harder to come by at Amazon.com, Best Buy, Target and Wal-Mart. He expects iPod sales to reach 21 million in the current quarter, down 5 percent from last year.

Wu says: “Frankly, we find these sell-outs on iPods surprising given how difficult the macroeconomic environment is, putting a crimp on consumer spending. From our assessment, we believe iPod is holding up better than most, due to its relatively low ASP (average selling price) and strong consumer understanding of the value it provides.”

Wu also sees growing adoption of Mac computers and iPhones. He cites research showing that Microsoft Windows’ operating system market share dropped below 90 percent in November, while Apple’s Mac OS X, which is used on Macs and iPhone, grew its share to 9.25 percent.

Other analysts are also noting Apple’s strength in the tough economic climate. More specifically, a new report from research group ChangeWave that shows Apple’s new Macbook gaining traction.  In the group’s November survey, 33 percent of respondents said they plan to buy an Apple laptop over the next 90 days, while 27 percent plan to buy an Apple desktop. In the same survey a year ago 29 percent planned to buy an Apple laptop, and 29 percent a desktop.