Microsoft has finally updated the official Windows 7 website page with download links.

Download Windows 7 Public Beta

Scroll down to bottom and you'll find drop-down boxes to select your language to download Windows 7 beta.

The 32-bit version of Windows 7 Beta is available in five languages: English, German, Japanese, Hindi, and Arabic. The 64-bit version is available in English, German, Japanese, and Arabic. Windows 7 Beta is available for a limited time, to the first 2.5 million people who download the software. Just choose the version that fits the system you'll be using for the test, pick your language and click go to register for and download the Beta.

Everything is running fine now and you'll not see any server busy error.

Windows 7 Beta Release Notes

Windows 7 FAQ

Windows 7 Official Homepage

Thanks to Vishal for information