Smartphone OS Showdown: Apple, Google, Microsoft, RIM Gear Up for Battle

If you're in the market for a new smartphone, don't even think about going down to your local cellphone retailer or AT&T/Sprint/T-Mobile/Verizon retail store to get a new device, at least not yet. Every major smartphone platform including , , , and is getting an overhaul with lots of new features, and, presumably, new hardware to go along with it starting in the fall.

Yes, smartphone OS updates happen around this time almost every year, but this time it's different. In 2012, it's not only about software refreshes, but a potential final stand for two smartphone competitors struggling for relevance in an Android and iOS-centric world.

Research In Motion is and for current keyboard-centric BlackBerry devices. Many critics believe the upcoming touch-centric BlackBerry 10 refresh is the company's last chance to maintain relevance in a post-iPhone world.

Microsoft can't get a significant number of users to , but the company is doubling down with new features and hardware support in the recently announced . Google, meanwhile, may be only days away from announcing . And this fall, Apple will release iOS 6 and, presumably, a .

Here's a rundown of the highlights coming this year for Android, iOS, BlackBerry, and Windows Phone.