Things are going so well for Apple (Nasdaq: AAPL) right now that even the bad news is pretty good.

According to Fortune, a Wall Street analyst is lowering his quarterly sales estimates for iPhone 4 by 17%. Kaufman Bros. analyst Shaw Wu now sees 7.5 million units sold in the third quarter instead of 9 million, and thinks the overall consensus of "8.5 million iPhones for the June quarter may likely prove too aggressive."

This shouldn't affect long-term shareholders in the least, however. Wu is only lowering his estimates because supply constraints may prevent Apple from producing enough phones to meet demand. That demand isn't going to subside, of course, and the sales will be made up in the following quarters.

I don't think AT&T (NYSE: T) is too happy with this news, however. If it is true that iPhone for Verizon (NYSE: VZ) is on the horizon, then delayed sales could translate to lost customers. With many itching to break free from AT&T, the company knows that any iPhone it sells now locks customers away from Verizon for the length of the two-year contract. The more these sales are delayed, the more customers would be willing to wait for an alternate carrier.

Meanwhile, let's not forget about Apple's iPad, which has been flying under the radar during the iPhone 4 hype. Digitimes says Apple has ordered up more than two million iPads from its Taiwan suppliers for July, "with 58-60% for the Wi-Fi and 3G hybrid model despite Wi-Fi only models having stronger sales in the first half of 2010." Kaufman analyst Wu, who lowered his iPhone sales estimates, raised his third-quarter iPad projections from 3.3 million 3.5 million.

So despite the "bad" news that insatiable iPhone 4 demand may result in fewer near-term sales, it looks like Apple is going to ride this dynamic iPhone/iPad duo for a long time to come.