Microsoft has announced SharePoint Products and Technologies 2007 (SP1) support for SQL Server 2008. See http://technet.microsoft.com/en-us/library/cc262485.aspx for MOSS and http://technet.microsoft.com/en-us/library/cc288751.aspx for WSS. (look towards the bottom)

 See my posts on upgrade http://blogs.msdn.com/mikewat/archive/2008/08/11/upgrading-sharepoint-sql-servers-to-sql-server-2008.aspx and new features http://blogs.msdn.com/mikewat/archive/2008/08/19/improving-sharepoint-with-sql-server-2008.aspx