Demand for new MacBooks outstrips supplies

The new MacBooks are hot -- and we're not talking about the lap-scorching temperature of their aluminum unibodies.

Apple's (AAPL) online store is currently showing a 7- to 10-day delay in shipping two models of the MacBook Pro -- the high-end ($1,500) 13-inch and the entry-level ($1,700) 15-inch.

According to Piper Jaffray's Gene Munster, who tracks product lead times, Apple has never had a 7-10-day delay in the 13-inch MacBook -- the one recently re-named the MacBook Pro. The most significant delay he's seen was a record 5-7 days, set more than two years ago.

In addition to the shipping delays, he says, some Apple retail stores are experiencing shortages of selected 13-inch MacBook Pros. Of the 10 stores his team contacted, seven were sold out of at least one 13-inch model.

In a note to clients issued early Tuesday, Munster wrote that this "sign of strong demand for Apple's most popular computer" gives him "increased confidence" in his estimate of 2.2 million Mac unit sales for the fiscal quarter that ended June 27.

Munster also notes that NPD's surveys of U.S. retail outlets showed Mac sales down only 3% in April and May -- considerably less than the 10% he had anticipated. When NPD releases its numbers for the June quarter -- which will include June sales -- Munster expects them to be up 1%.

We'll learn more when Apple reports its third-quarter earnings on July 21. Tune in here for live coverage of the company's earnings call with analysts scheduled to begin at 5 p.m. EDT (2 p.m. PDT).