Dell is late to the game with its tablet play. By launching the Streak more than four months after the iPad hit the shelves, Dell has gifted Apple a huge head start, effectively letting the consumer tech giant redefine the tablet space. The end result is that Apple has already sold more than 3 million iPads, and for many consumers, "tablet" equals "iPad." If anything, the Dell Streak is more likely to come up against Apple's iPhone. With a 3.5-inch screen, the iPhone is closer in size to Dell's mini-tablet. Both devices offer voice capabilities, unlike the iPad. While the idea of a smartphone/tablet hybrid is intriguing, Dell must somehow carve out a niche between two well-defined technologies. Cost could also be a factor working against Dell's mini-tablet. The Streak will cost $299.99 on a two-year contract from AT&T ( T), $549.99 without. The iPhone 4, in contrast, costs $199.99 on a two year contract from AT&T. Dell's attempts to market the Streak have left much to be desired. The Streak generated some buzz after it was previewed at CES, but Dell waited until June to debut the device ... in the U.K. Initially, Dell had promised that the device would be available in the U.S. in late July, although this was pushed back until mid-August, much to chagrin of Dell zealots. Consumers can submit pre-sale orders for the Dell Streak starting Thursday, with the tablet becoming generally available on Friday. Dell shares plunged 44 cents, or 3.53%, to $12.01 on Wednesday, outpacing the broader selloff in tech stocks that saw the Nasdaq fall 2.79%. -- Reported by James Rogers in New York Follow James Rogers on Twitter.