Apple’s new iPad is on shelves today at Apple stores across the country. Among those already in line for the updated tablet? Apple co-founder Steve Wozniak. The avid Foursquare user, checked-in at a Los Angeles mall on Thursday afternoon.

“Starting a line for the new iPad tomorrow,” Wozniak tweeted.

Lines have been forming at Apple stores around the country. In Bethesda, The Washington Post’s Cecilia Kang reported, there were already a few dozen people waiting in front of the Apple store on Bethesda Avenue when doors opened at 8 a.m.

For those who aren’t keen on hanging out at the Apple store, retailers such as Best Buy, Target, Walmart and carrier Verizon and AT&T are also selling the new iPad.

Reviewers say that the updated device will keep Apple on top of the tablet market, though the iPad’s minor changes— while impressive — are not likely to extend the company’s lead.

In his review, The Washington Post’s Joshua Topolsky described the new device’s display as looking like “glowing paper,” with crisp text and vivid images. But he also said that users happy with their iPad 2 tablets shouldn’t feel compelled to run out and buy the newest version.

Apple briefly topped the $600 per share mark in trading on Thursday morning, indicating that the company shows no signs of slowing down. Analysts have said that Apple shares may rise above $700, as iPad sales climb, Bloomberg reported.

But not everyone is happy about the new iPad launch. Protestors who have signed a petition asking Apple to improve working conditions in supply chain factories in China organized demonstrations on launch day in Washington, New York and San Francisco. The protestors are asking Apple to release a strategy for protecting supply chain workers ahead of product launches, when factories are rushing to move products to stores.

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