Windows 7 beta has been available for download on Microsoft website for both 32 bit and 64 bit systems. For a beta version, it has been an amazing product with efficiency, stability, usability and compatibility being the most important features for me.
Microsoft has just announced the release candidate of Windows 7. Windows 7 RC became available for MSDN subscribers on April 30th and will be available for download for general public on 5th May. According to a newsletter Microsoft sent to its beta testers including myself, this RC will continue to be available for download till end of June.