It???s also well worth reading what you can find on MSDN. The programming guide for 64 bits is at: <a href="http://msdn.microsoft.com/en-us/library/bb427430(VS.85).aspx">http://msdn.microsoft.com/en-us/library/bb427430(VS.85).aspx</a> and the data types article is at: http://msdn.microsoft.com/en-us/library/aa384264(VS.85).aspx.