The Next Web posted a story that the public beta of Windows 8 is planned for late February 2012

Mobile World Congress kicks off right at the end of February, and it’s unlikely that Microsoft would release the Windows 8 beta there; Windows Phone will surely be the primary focus of the company’s MWC efforts. It’s more likely, therefore, that we’ll see the beta released at least a week earlier, perhaps around February 20 but this is pure speculation at this point if the rumor about a February date holds true.

The exact feature set of the beta has not yet been finalized, but given that it will be a public release, it’s likely to be reasonably complete.

  Windows 8 beta will be released in late February