Riffing on the fact that some consumers are using the phone as their primary digital screen, Motorola and AT&T on Wednesday unveiled the ATRIX 4G, which puts the power of a Netbook, and then some, in the palm of a user’s hand.

Billed as a gaming, music and video-on-the-go powerhouse, the Android 2.2 unit runs Firefox 2.3 and has Flash integration on a 4-inch screen. It can be juiced to a custom docking station complete with keyboard and an 11.6-inch screen, as well as HDMI output for TV connectivity (up to 720p HD on release, which Motorola plans to upgrade to 1020) and three USB ports for a mouse, speakers or gaming controller. As a bonus for business users, it has an integrated Citrix receiver for VPN access. The Atrix runs on a dual core (2GHz total) processor , with 1GB of RAM, and offers up to 48GB of memory – 16GB on board and an optional 32GB microSD card.

Motorola also introduced the XOOM tablet, for Verizon, which it billed as “the first tablet PC built to run on the Android 3.0 OS” (dubbed Honeycomb). The device, which features a 10.1-inch (16:9), 1280×800 display, will connect to the new Google Mobile Innovation service offering HD-optimized books, music and movies. It debuts in 3G in the first quarter, with an upgrade to 4G expected in the third quarter.