Is there room for one more giant in the battle for smartphone supremacy?

Microsoft (Nasdaq: MSFT) hopes so, after unveiling its Windows Phone 7 operating system on Monday.

The company has an uphill battle, despite a pretty clever marketing campaign. Yes, Microsoft has been in the mobile space for awhile, but this is its bold bet to make a splash in a world overrun by BlackBerrys, iPhones, and Androids.

Several handsets running WP7 will hit the market next month, just in time for the holiday shopping season. Steve Ballmer has ordered anyone who mentions WP7 and Kin in the same sentence to be terminated.

Oops! Just kidding. Sorry about that, Steve.

Briefly in the news
And now let's take a quick look at some of the other stories that shaped our week.

  • Sirius XM Radio (Nasdaq: SIRI) swapped out debt for even cheaper debt with later maturities, announced robust third-quarter subscriber metrics, and even scored a Moody's upgrade. What did you do this week?
  • Wal-Mart (NYSE: WMT) began selling Apple's (Nasdaq: AAPL) iPad this weekend. Verizon Wireless will begin selling a bundled version of the Wi-Fi tablets by month's end.
  • IMAX (Nasdaq: IMAX) announced its first joint venture in Germany, with European exhibitor CinemaxX. Despite the name, CinemaxX is not an adult-entertainment company -- though that would certainly open a new door for the bigger-than-life cinematic specialist.
  • MGM Resorts (NYSE: MGM) is shuffling assets around and issuing new shares in an attempt to get back on track. This is a long shot, but MGM is always up for a good gamble.

Until next week, I remain,

Rick Munarriz

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Microsoft and Wal-Mart are Motley Fool Inside Value picks. IMAX is a Motley Fool Rule Breakers choice. Apple is a Motley Fool Stock Advisor selection. Motley Fool Options has recommended a diagonal call position on Microsoft. The Fool owns shares of Apple, Microsoft, and Wal-Mart. Try any of our Foolish newsletter services free for 30 days.

True to its name, The Motley Fool is made up of a motley assortment of writers and analysts, each with a unique perspective; sometimes we agree, sometimes we disagree, but we all believe in the power of learning from each other through our Foolish community.

Longtime Fool contributor Rick Munarriz recommends windshield wiper fluid when trying to look back. He owns no shares in any of the stocks in this story and is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.