by Gabe BullardApple's highly-anticipated iPad tablet computer goes on sale Saturday, and three area retailers are preparing for an onslaught of customers.The Apple retail store, select Best Buys and the Mac Authority are the only area stores that will have iPads available upon opening Saturday.Mac Authority store manager Jeffrey Jewell is expecting a line outside his store when he opens. But along with healthy iPad sales, Jewell says he's anticipating a strong market for accessories."This is certainly…there's a whole new product line that has been created for this device so I do assume to push numerous other [products] to accompany the iPad," he says.Jewell says he and his technicians are also anticipating training from Apple for iPad repair services.The Mac Authority did not sell iPhones when they were released, and Jewell says this will likely be the biggest product launch he's seen at his store.