The new requirements for SharePoint Server 2010, hence Project Server 2010 have been disclosed on TechEd:

– 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
– SharePoint Server 2010 will require a standards based browser to author content (XHTML 1.0 compliant) so will not support IE 6.

You can read more about this at Brian Smith’s blog.