Apple Inc. (AAPL) may sell 600,000 of the second version of the iPad when it debuts this weekend, reports Bloomberg. By comparison Apple sold 300,000 of the original iPad in 24 hours. The iPad 2 goes on sale on Apple’s website at 4 a.m. New York time and they will be available at Apple stores at 5 p.m. in the U.S.

The iPad line is the fastest-selling technology product in history, measured by revenue, said Tim Bajarin, an analyst at Creative Strategies Inc.

“Apple has such a huge lead… Competitors are going to be chasing Apple for many years,” said Bajarin.

The iPad 2 will be available at 236 Apple stores and 10,000 other stores of AT&T, Verizon Wireless, Wal-Mart Stores, Best Buy and Target Corp. By comparison the iPad was available in 221 Apple stores and 1,100 other outlets, according to Piper Jaffray’s Gene Munster. Through December, Apple sold a total of 14.8 million iPads, generating $9.6 billion in sales.

“The iPad 2 is essentially the tablet market,” said Ashok Kumar, an analyst for Rodman & Renshaw. He predicts Apple will sell 35 million units of the iPad this year. “That very well could be conservative.”

The iPad has been popular with businesses as well, including JPMorgan Chase, Wells Fargo and Archer-Daniels-Midland.

The iPad may bring in revenue of $16.3 billion for Apple, according to Toni Sacconaghi, an analyst at Bernstein. The iPhone didn’t reach that level until more than three years after its release.

Competing devices from Motorola and Samsung Electronics Co. are struggling to match Apple’s success and price.

As new tablets come to the market this year, there could be a “bubble” of rival devices, Mark Moskowitz, an analyst at JPMorgan, said in a research note. That would create more supply than demand.

“The technical and form factor improvements of the iPad 2 stand to make it tougher for the first generation of competitive offerings to play catch-up,” according to Mark Moskowitz, an analyst at JPMorgan.