The iPhone's booming popularity continues to keep Apple sailing comfortably through rough recessionary seas, more than making up for declining revenue in its Mac and iPod businesses.

Apple sold 5.2 million iPhones during the quarter, compared to 717,000 during the year-ago quarter. iPod touch sales grew 130 percent during the quarter as a result of the growing popularity of the App Store, Apple CFO Peter Oppenheimer said Tuesday during Apple's third quarter earnings call.

However, the market's response to the iPhone 3GS has been so strong that Apple is currently unable to meet demand, according to Oppenheimer.

In its third quarter, Apple reported earnings of $1.23 billion, or $1.35 per share, up 15 percent from the $1.07 billion and $1.19 per share it racked up during the year-ago quarter. Revenue rose 12 percent during the quarter to $8.34 billion. Apple's gross margin for the quarter ended June 26 was 36.3 percent, up from 34.8 percent during the previous quarter.

Wall Street analysts had expected revenue of $8.2 billion and earnings of $1.17 per share. Apple in its April earnings call had forecast revenue of $7.7 billion to $7.9 billion and earnings of 95 cents to $1 per share.

Apple offered typically conservative guidance for its upcoming September quarter, forecasting revenue of between $8.7 billion and $8.9 billion, earnings of $1.18 to $1.23 per share and gross margin of 34 percent. That's due in part to the rising cost of many key components, Oppenheimer said.

Mac sales rose 4 percent during the quarter to 2.6 million units, but Mac revenue fell nearly 8 percent. That was partially the result of the lower-priced Macs Apple announced in June at its Worldwide Developer Conference, which included a 13-inch MacBook that starts at $1,199 and can be equipped with up to 8 GB of RAM.

Acknowledging the "significant changes" to Mac pricing, COO Tim Cook said that Apple doesn't plan to make any major alterations to its Mac business. "We are not thinking fundamentally differently about the Mac business than we were before," Cook said in a Q&A session after the call. "We won't put the Apple brand on a product that doesn't stand for innovation and doesn't have the legendary ease of use that we're known for."

Apple's revenue from iPod sales dropped 11 percent during the quarter, while unit sales fell 7 percent to 10.2 million. But Oppenheimer said the iPod decline was expected given the cannibalization effect from iPhone and iPod touch sales and because Apple reduced channel inventory by more than 400,000 units.

Investors greeted Apple's Q3 results as children would greet an approaching ice cream truck: Apple shares were up $6.95 to $158.46 in Tuesday after-hours trading.