If you were hoping to see Apple get some competition in the suddenly burgeoning market for tablet devices, Dell has what might be the first viable contender: The company's Streak tablet goes on sale this week in the United States after a trial run in the United Kingdom.

The Dell Streak doesn't directly target the iPad, however, although future models might be closer in size and functionality. Today's initial Streak version is a weird hybrid of a smartphone and an iPad, offering a 5" multi-touch WVGA (800 x 480) screen, a 1GHz processor, 512MB of ROM, 512MB of RAM, and a 2GB MicroSD card for storage. (It's removable and expandable to 32GB.) The device runs Google's Android OS.

Oddly, the Android OS included with Streak is an older version—version 1.6—that doesn't feature many of the niceties of the 2.x versions. But Dell says the Streak will be upgraded to the latest Android version—version 2.2—later in the year. It does feature Google Maps with free turn-by-turn navigation, text-to-voice, and real-time Facebook and Flickr updates.

Like a smartphone, the Streak is sold through wireless carriers—the US partner is AT&T—so it comes in both subsidized and unsubsidized versions. If you opt for a two-year AT&T data and voice contract (the Streak can make and receive phone calls), it costs $300. Without a contract, the device goes for an iPad-like $550, a pretty lofty sum for such a product.

According to Dell, customers interested in preordering the Streak can do so on August 12, while broader device sales will start the next day, on August 13. Dell plans additional Streak models, with larger screen sizes and perhaps different form factors, in the future.

Those waiting for a Windows-based iPad competitor face a longer wait. Although some PC makers will no doubt offer slate-like PC designs in time for the holiday 2010 season, the real competition won't arrive until 2011. That's when devices based on Intel's "Oak Trail" system-on-a-chip arrive. Oak Trail is a next-generation version of the Atom platform and will offer much better battery life and processing power than today's low-end Atom-based systems.