Apple sold about 525,000 iPhones at Apple and AT&T Inc. stores in the first weekend since its June 29 launch, according to anaysts.

The weekend stats are in and Apple has sold half a million iPhones in the first weekend. Selling 500,000 units of any product during its inaugural weekend launch is big.

According to Gene Munster, an analyst at Piper Jaffray, that's exactly what Apple's iPhone managed to pull off. After originally expecting Apple to sell "only" 200,000 iPhones on Friday and Saturday, he's now estimating that Apple sold a half-million iPhones from start of sales at 6pm on Friday until close of business on Sunday even with supply issues at AT&T store.

According to their survey, 95% of buyers purchased the 8GB model with 50% of all buyers making the switch from another carrier to AT&T. Great news right? Maybe, but in a potentially worrying trend, Apple is showing a marked decrease in iPhone availability at their retail locations this morning. While stores showed a 100% iPhone availability (they don't break it down by 4GB and 8GB models) on Saturday which dropped to 84% on Sunday, Apple's retail channel is showing a further decline in availability for Monday across Apple's brick and mortar retail business. In particular, Californians not living in San Francisco will have a tough time locating the device with 34 of 36 stores bleeding red on Apple's retail locator site -- a potential supply problem especially if AT&T shops remain void of product.

The iPhone, which combines a phone, Web browser and a music player, went on sale on Friday.

Sure, you can still order on-line albeit with that same 2-4 week delivery delay we've seen since day 1.