Download Windows 8 Developer Preview 32-bit and 64-bit ISO (Direct Download Links)

Microsoft finally released the Windows 8 Developer Preview  or pre-beta version of its next Operating System showing off the operating system at its current stage.Though technically designed for developers, no registration is required, so anyone can download and install it.Since this is a prebeta version, you'll want to install the OS on a spare PC or in a virtual environment so that it doesn't interfere with your production or work machine.

New Features in Windows 8 :

1. Interactive Tiles interface Metro Start Screen :
The interactive tiles make the Windows 8 Start Screen infinitely more useful than the iPad’s home screen, which is little more than an app directory.

2. New and Improved Task Manager :
The Task Manager is now displayed as a heatmap, making it easy to identify resource-gobbling applications or processes. There’s also an incredibly useful App History Tab, which exposes the apps that have been downloading the most data over your wireless network – which could potentially be a huge cash saver if you’re paying for data by the MB on a 3G connection.

3. USB 3.0 support :
It comes with support for USB 3.0 which means ultra fast copy and transfer of data between two compatible devices

4. New ribbon UI :

5. Internet Explorer 10 :Metro Interface

Metro style Internet Explorer 10 provides a fast and fluid touch-first browsing experience that’s all about your sites, making them feel increasingly more app-like. It comes with faster performance, better security protection, more hardware acceleration, and site-ready HTML5 support. The address bar is at bottom and not visible always.

6. App Model :

    Windows 8 will have a App Store is referred to in relation to the evolution of virtualization capabilities in   Windows 8,specifically Desktop as a service(DaaS).

Windows 8 Developer Preview ISO (Direct download Links) :

Windows Developer Preview with developer tools English, 64-bit (x64)
DOWNLOAD LINK (4.8 GB)
Sha 1 hash - 6FE9352FB59F6D0789AF35D1001BD4E4E81E42AF

All of the following come on a disk image file (.iso).

• 64-bit Windows Developer Preview
• Windows SDK for Metro style apps
• Microsoft Visual Studio 11 Express for Windows Developer Preview
• Microsoft Expression Blend 5 Developer Preview
• 28 Metro style apps including the BUILD Conference app

Windows Developer Preview English, 64-bit (x64)
DOWNLOAD LINK (3.6 GB)
Sha 1 hash – 79DBF235FD49F5C1C8F8C04E24BDE6E1D04DA1E9
Includes a disk image file (.iso) to install the Windows Developer Preview and Metro style apps on a 64-bit PC.

Windows Developer Preview English, 32-bit (x86)
DOWNLOAD LINK (2.8 GB)
Sha 1 hash - 4E0698BBABE01ED27582C9FC16AD21C4422913CC
Includes a disk image file (.iso) to install the Windows Developer Preview and Metro style apps on a 32-bit PC.

System Requirements

Windows Developer Preview works great on the same hardware that powers Windows Vista and Windows 7:

• 1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor
• 1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit)
• 16 GB available hard disk space (32-bit) or 20 GB (64-bit)
• DirectX 9 graphics device with WDDM 1.0 or higher driver
• Taking advantage of touch input requires a screen that supports multi-touch

How to activate Windows 8 Developer Preview

Since it is a developer preview of Windows 8 so you don’t need to activate this build after installing the developer preview,hence doesn't need key.

via Microsoft Msdn blogs

Note : All images as per released by microsoft during the keynote of its 2011 "Build" conference.