The sleek, translucent turquoise-and ice-coloured iMac personal computer -- priced at $1,299 -- went on sale on Saturday, with some stores opening at midnight Friday night.

"From talking to resellers, it looks very positive," said Tami Begasse, a spokeswoman for the Cupertino, Calif.-based computer maker. "I just don't have any definitives yet."

Apple said last week it had advance orders for more than 150,000 units, the most pre-orders ever for an Apple product.

Apple's shares jumped $1.44 to $41.94 on Nasdaq after earlier rising as high as $42.81 -- a point its once-downtrodden stock has not seen in nearly three years.

Apple's shares were among the top 10 most active on the Nasdaq stock market, with more than eight million shares changing hands.

"This was beyond our wildest dreams," said Paul Ramirez, vice president of marketing at ComputerWare, a chain of 10 Apple-specific stores in the San Francisco Bay Area.

Ramirez said ComputerWare, which started selling iMacs at midnight on Friday and sold 225 iMacs between midnight and 2 A.M.

"Saturday exceeded our best day in history by 60 per cent...It's Christmas, plus 60 per cent in August...That is totally insane," Ramirez said.

Apple said about 25 Apple speciality retailers took part in the "Midnight Madness" across the United States for the iMac launch, not including regional retailers.

While the launch was certainly no match for the hype surrounding that of Microsoft Corp's Windows 95 operating software, some retailers were calling it one of the most successful Apple product launches in years.

"The whole weekend was great," said Tony Violanti, vice president of retail sales at ComputerTown, a five store chain with stores in New England and Arizona. "It was the best in pre-orders we have ever had for any Apple product...We had a lot of first time customers."

Ramirez said that over the entire weekend, ComputerWare sold well over 600 iMacs, including pre-paid back orders.

He said ComputerWare was working with an industry analyst to poll the first 500 customers, to determine how sales are split between current Mac owners or to new users.

"I would say it's a successful launch," said Lou Mazzucchelli, a Gerard Klauer Mattison & Co analyst. "Every store that I've seen a report of, or some of the stores I was in this weekend, were all sold out before noon...The interesting thing is...the demographics were great."

Mazzucchelli said some very early anecdotal evidence suggests that Apple's ad campaign, which is focusing on the simplicity and quick access to the Internet, is drawing new users and PC users, not just the Macintosh faithful user.

Apple said last week it would spend $100 million on a major advertising blitz through the end of December, including Prime time television ads that began running last night.