Earlier this month Intel published its HD Graphics beta driver for the Windows 8 Release Preview, you can download it over here.
This software driver package will install the beta graphics driver for the Intel® HD Graphics 3000/2000 & Intel® HD Graphics 4000/2500 for Windows 8* Release Preview.+
These beta drivers will not function with any other product. View the README file for installation information and the RELEASE NOTES for driver version details. This driver package contains version 18.104.22.168.2770 (22.214.171.12470) for Windows 8*. This package also includes the Video BIOS files. According to the license agreement, these preview drivers are provided "as is".
These software drivers are generic versions and can be used for general purposes. However, computer original equipment manufacturers (OEMs) may have altered the features, incorporated customizations, or made other changes to the software or software packaging they provide. To avoid any potential installation incompatibilities on your OEM system, Intel recommends that you check with your OEM and use the software provided by your system manufacturer.
Intel and the computer original equipment manufacturer (OEM) may not provide technical support for some or all issues that could arise from the usage of this generic version of software drivers.