A few days ago, someone ask me where he was able to find some information about SharePoint and Office development. Here are some interesting links:
SharePoint 2010: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=f0c9daf3-4c54-45ed-9bde-7b4d83a8f26f
SQL Server 208 R2: http://www.microsoft.com/downloads/details.aspx?familyid=FFFAAD6A-0153-4D41-B289-A3ED1D637C0D&displaylang=en
Office 2010: http://www.microsoft.com/downloads/details.aspx?FamilyID=b90fadab-f4f9-4452-aa61-ed7bd5d8111e&displaylang=en
There are others SDK and Training Kits that are available. Do not hesitate to do have a deeper look to.