It looks like Motorola is unlocking the Atrix bootloader with the Gingerbread update
2.3.3, which unfortunately means that the phone still won't be able to use the new video chat in GTalk which requires 2.3.4. But, the update will allow the use of the traditional fastboot oem unlock command to unlock the bootloader. And, an unlocked bootloader means full support for custom ROMs and kernels. Given the power of the Atrix and the interesting dock features, it should be very interesting to see what kind of tweaks and custom features the mod community builds once they are able.
BriefMobile is confirming the unlock on the Chinese and AT&T variants of the Atrix, but expect that the unlock will come to all Atrix carriers around the world.
source: BriefMobile via Android Police