SPSFAQ

The requirements for sharePoint 2010 :
SharePoint Server 2010 will be 64-bit only.
SharePoint Server 2010 will require 64-bit Windows Server 2008 or 64-bit Windows Server 2008 R2.
SharePoint Server 2010 will require 64-bit SQL Server 2008 or 64-bit SQL Server 2005.

Browsers:
read on the web site : http://www.spsfaq.com/2009/05/requirements-for-sharepoint-2010.htm#links - SPSFAQ see also :

http://blogs.msdn.com/sharepoint/archive/2009/05/07/announcing-sharepoint-server-2010-preliminary-system-requirements.aspx