One of the newest mobile phone accessories coming out this fall may revolutionize mobile computing.

The Motorola Droid Bionic is slated to carry an optional Webtop adapter starting this September. With the adapter, users can essentially turn their smartphone into a large tablet or netbook, by projecting the screen onto a monitor or digital television through an HDMI cable.

If the technology takes off, mobile devices may take a larger chunk of the computing market – PC sales are already slumping as smartphone and tablet sales rise, despite the down economy. With the ability to view multimedia and games through the Webtop, computer owners that use their PCs mostly for recreational purposes may have no need for the bulky, expensive hardware.

Armed with a wireless keyboard and mouse, users can access cloud computing-based services like Google Docs and Microsoft Office Live, making the storage capabilities of desktops and laptops less necessary.

When introduced in January, the Droid Bionic features up to two GHz in processing power and runs on a 4G network, making it one of the most capable smartphones on the market. The device has a powerful camera, meaning media can both be easily captured and projected with the Webtop device.