Cellular South today announced the upcoming availability of the HTC Merge, the world’s first smartphone to come pre-loaded with the Amazon Appstore for Android. The device, which will be available next month for a yet-unannounced price, is an Android 2.2 side-slider with a 3.8-inch touchscreen, full QWERTY thumbboard, and HTC Sense user experience layer. Merge also will be Cellular South’s first Android world phone.

Merge will actually ship with both Amazon’s app store and the traditional Android Market familiar to current users of Google’s mobile OS. “The Merge will have both the Amazon Appstore for Android pre-loaded as well as the Android Market app on the device,” according to Dave Miller, Media Relations Manager for Cellular South.  “We are excited about the partnership with Amazon as they are featuring a free paid app of the day for consumers, which is a nice perk.  Amazon also has the benefit of one-click purchases.”

Bully for Cellular South customers, but the big news here is how quickly Amazon is edging into the mobile space with their customized, branded Android plays. AT&T has already announced  – actually, Angry Birds developer Rovio announced for them – plans to install Amazon Appstore on forthcoming devices, and  Amazon’s Cloud Player “media locker” just went live in the wee hours of this morning.

At the risk of beating a horse to death here, it’s hard to over-emphasize how well situated Amazon is to battle everyone from Apple to Barnes & Noble to Netflix in the war for your digital media dollars. Stay tuned – 2011 is getting more interesting by the day.