Changes will happen automatically in the background; Motorola Atrix 4G will also receive an update

Sideloading on AT&T

An AT&T spokesman has confirmed some smartphones in AT&T's current lineup will be updated to allow installation of applications from outside the Android Market. This comes after we published a screen shot that states the Samsung Captivate and HTC Inspire 4G and Aria will soon receive access to applications from outside the Android Market, a process known as "sideloading." AT&T has also confirmed to us that the LG Thunder will receive the update to allow non-market apps. Here's the official word:

In March, we announced our intent to provide AT&T Android customers access to third-party application stores. [story] Future Android devices (including the recently launched Samsung Infuse 4G) [story] will allow users to change their settings in order to access this content. Over the next few weeks, we will also roll-out this capability to existing devices in our base for which an upgrade is possible. Users will not need to take any action as their phone will receive the update automatically. 

Previously, installation of non-market apps required hacking of the phone, or a tool like the Sideload Wonder Machine. With this silent update -- note that you won't actually have to do anything; AT&T will push it to your phone automatically -- you'll now be able to install applications directly from developers, websites and, yes, finally, the Amazon Appstore.

And as for the Motorola Atrix 4G? AT&T says it's working with Moto, which will provide the update for non-market apps in a future maintenance release.