There's a version of AMD Phenom CPU which is 6 cores. Would Windows 2008 64 bit & SQL Server 2008 64 bit make use of all the cores? Any special settings of the OS or sql server needed to benefit from all the 6 cores?
Yes you can use all cores the limitations are on sockets. Standard can only go up to 4 sockets. Here is the edition comparison chart.
Here is the comparison chart for SQL server