As we head toward the release date for Apple's next big iPhone, the 3GS, pundits and experts are stepping forward with some pretty robust sales estimates.

At the same time, AT&T

T loading...

Quote  |  Chart  |  News  |  Profile

[T  Loading...      ()   ] is taking issue with the legions of blogs and websites reporting that the company is sold out of its iPhone allocation.  Let's hit that one first: a spokesperson tells me that indeed, pre-orders are now showing a 7 to 14 day delivery delay beyond the June 19 release date for 3GS, but that AT&T WILL HAVE the phones on store shelves on Friday.  How many and for how long remains to be seen, but rumors that the phone is already sold out are simply not true, I'm told.

Source: Apple New iPhone 3GS

Why the delay then?  "Convenience," of course.  I don't know what that means but somehow AT&T believes that a week or two delay in taking delivery of the phone is a small price to pay for the "convenience" of being able to get on the advance wait-list.  (Nope, I don't get it either, but that's what I was told.)

Now, on to sales projections:  Piper Jaffray anticipates 500,000 to 750,000 units will sell in 3GS's first weekend, compared to the 1 million iPhone 3G's that sold in its first weekend a year ago.  (Palm's Pre did anywhere from 50,000 to 100,000 units for Sprint in its first weekend, depending upon whom you believe, by the way.)

Piper also says that Apple

AAPL loading...

Quote  |  Chart  |  News  |  Profile

[AAPL  Loading...      ()   ] will sell 1 million units before the quarter ends, or about 20 percent of the 5 million estimated iPhones expected to ship on the quarter.

• Smartphones Rock, But 'Free' Rules Supreme

I spoke with Gene Munster about this and he told me that had Apple delayed 3GS for any reason, Piper would have had to reduce its Apple numbers on the quarter, so this is right in line with earlier expectations.  However, other analysts may be looking into raising their numbers ahead of Apple's earnings report next month.

RBC for one is looking at channel checks and should come out with anticipated iPhone sales figures shortly.

But the Piper numbers are intriguing.  For one, they suggest another blockbuster release for Apple.  For another, you wonder if the numbers would be even stronger if Apple hadn't cut the price of the existing 3G to $99.

It's also not clear that either AT&T or Apple will release any kind of sales figures next week.  But that said, it seems investors, the Street, Apple and AT&T are preparing for some pretty significant numbers.

We shall see.

Questions?  Comments?