As is common between all AT&T Android handsets, sideloading applications has become a distant dream. There have been workarounds, of course, but they’ve always required some sort of third party utility that requires the use of a PC every time you need to install a .apk file. (This can be inconvenient if you’re on the go and someone has sent you a .APK file via email.)
The folks at XDA have figured out a way to get the functionality enabled on the Motorola Atrix 4G, though. You’ll need to know your way around a command line, and if you’re on Windows you’ll need to download sqlite.
After you get through all of that, though, you’ll be able to sideload applications just like the rest of us are able to. It wasn’t said if rooting your device would be a requirement, but we’ll just go ahead and assume it is until we can scrape together some more information about the process. Check it out for yourself over at XDA. [TalkAndroid]