Today AMD announced ATI XGP (External Graphics Platform), a new external PCI Express (PCIe) 2.0 graphics platform, designed to deliver enthusiast-class desktop graphic performance and true multimedia upgradeability to notebooks.

The ATI XGP is a technology that capitalizes on PCIe 2.0 to deliver enthusiast-class graphics via a connected cable to an externally powered and cooled device.
ATI XGP delivers up to 4.0 Gbyte/s in each direction in bandwidth communication between the notebook and external graphics, whereas previous consumer level external solutions were limited in graphics bandwidth.
ATI XGP is fully optimized for new AMD Turion X2 Ultra notebook platforms, also announced today.

AMD will launch the ATI XGP Technology first with the newly announced ATI Mobility Radeon HD 3800 series HD graphics card. The ATI XGP Technology delivers multi-GPU capabilities of scalable performance with ATI CrossFireX technology. The additional high bandwidth of the included USB 2.0 connectivity allows users to connect to a wide variety of USB-based devices, including external TV tuners, external Blu-ray players, and much more.

ATI XGP Technology is contained in an external chassis connected to the notebook via a specially designed self-latching, easy-connecting PCIe 2.0 cable from Japan Aviation Electronics Industry, Limited, a provider of electronic devices and connectors.
The cable also provides USB 2.0 connectivity directly to the notebook allowing for additional USB functionality.

One of the first companies to offer an actual product based on the ATI XGP technology is Fujitsu-Siemens. The Fujitsu-Siemens AMILO GraphicsBooster is based on ATI XGP. No pricing information is available at this point. AMILO 3000 is the new consumer product line of Fujitsu Siemens the company announced at the end of May.
More details on the ATI XGP site.