If you have a subscription to either MSDN or Technet then RTM SharePoint Server and Office Professional Plus 2010 RTM became available late yesterday for download. Since SharePoint Foundation 2010 and SharePoint Designer (SPD) 2010 are available for free they weren’t posted on either MSDN or Technet. Instead they can be downloaded directly from the Microsoft Download Center. Just check out the links below:
SharePoint Designer 2010 (32 bit) – http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=d88a1505-849b-4587-b854-a7054ee28d66
SharePoint Designer 2010 (64 bit) – http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=566d3f55-77a5-4298-bb9c-f55f096b125d
Remember that your installation of Designer must match the installation of any other office products. If you’ve installed Office X64 then you can only install SPD X64. If you’ve installed the 32 bit version of Office then you can only install the 32 bit version of Designer. You can install both SPD 2007 and 2010 on the same box, but since SPD 2007 only comes as a 32 bit app you can only install the 32 bit version of SPD 2010 with it.