deepak - Tue Jun 19 2012 22:26:25 GMT-0400 (EDT)

Steps to find this

1) Click the About the MAC option
2) Open the hardware section and check the processor
3) Map it from the below list
Intel Core Solo   32 bit
Intel Core Duo   32 bit
Intel Core 2 Duo   64 bit
Intel Quad-Core Xeon   64 bit
Dual-Core Intel Xeon   64 bit
Quad-Core Intel Xeon   64 bit   
Core i3   64 bit
Core i5   64 bit
Core i7   64 bit