Windows 7 beta is available to public. I had seen a demo at MVP open day on windows 7 and it was very impressive. I feel, Microsoft has implemented all things to required to make this OS a success with the lessons learn in Vista and seeing current customer expectations. I am very much excited to see the preview. You can also download the link from MS site. Check below link for more details.
http://microsoftblog.co.in/2009/01/10/want-to-download-windows-7/