Aug. 7 (Bloomberg) -- Apple Inc. Chief Executive Officer Steve Jobs introduced three thinner versions of the iMac desktop that may push computer sales to a record during the back-to- school shopping season.

``The iMac has been really successful for us -- we'd like to make it even better,'' Jobs said today at an event at Apple's headquarters in Cupertino, California. The two 20-inch models and the 24-inch version are made of aluminum and glass, which is easier to recycle, he said.

Updated iMacs should spur educational orders and push Mac shipments to a record 1.9 million or more units this quarter, Piper Jaffray & Co. analyst Gene Munster said. The Mac, Apple's biggest moneymaker, accounts for almost half of sales.

``It's a very sleek-looking design,'' said Romeo Dator, a San Antonio-based portfolio manager at U.S. Global Investors Inc., which has about $4.5 billion under management including Apple shares. ``It's cheaper, has more power and is better looking.''

The 24-inch version costs $1,799, $200 less than its predecessor. At about one-inch thick, the 20-inch and 24-inch iMacs are about a half-inch thinner than prior models, Apple said. All three new versions are available today.

Apple shares fell 22 cents to $135.03 at 4 p.m. New York time in trading on the Nasdaq Stock Market. They have gained 59 percent this year.

Apple's global share of personal computer sales reached a high of 3 percent in the second calendar quarter, up from 2.5 percent a year ago, Munster said, citing data from researcher IDC. Apple's other businesses include the best-selling iPod media player and the iPhone, which blends the iPod's audio and video features with a mobile handset. The iPhone came out June 29 in the U.S.

Mac Attention

Jobs, 52, won customers by updating Mac notebook and desktop machines with faster chips from Intel Corp. over the past year. Minneapolis-based Munster, who rates the shares ``outperform'' and doesn't own any, said in a report yesterday that a new iMac may draw attention away from the iPhone and back to the ``more significant story'' of the computer business.

Apple also discontinued the 17-inch version of the iMac and introduced a faster version of the Mac Mini, its least expensive Mac at $599. The new Mini, a system that's sold without a monitor, keyboard or mouse, is 39 percent faster than the prior model, company said.

New MacBook notebooks led a 73 percent surge in profit last quarter. The company sold 270,000 iPhones in the last two days of the quarter, and Jobs has said he expects Apple to sell 1 million by the end of the device's first full quarter of sales in September.

IPhone Success

``We think the iPhone is a pretty strong success,'' said Jobs, who was clad in his trademark black turtleneck and jeans.

Apple has no plans to create a Mac that uses the touch- screen interface that drives the iPhone, Jobs said. ``We think it makes a lot of sense in the iPhone, we're not so sure it makes a lot of sense in the Mac. So who knows?'' he said. ``I would classify that as a research project at this point.''

Apple also updated the $79 iLife software that comes with every Mac, which includes applications for photos, DVD and video. The company released a new version of its $79 iWork word processing and page layout software that adds a spreadsheet called ``Numbers.''

To contact the reporter on this story: Connie Guglielmo in San Francisco at cguglielmo1@bloomberg.net.

Last Updated: August 7, 2007 16:37 EDT