Windows Vista 64 & 32 Bit Difference?

What is the difference between 32 bit and 64 bit Vista?

IMO there is no difference between these two versions other than the support for various programs.

The basic difference is that a 32-bit process process 32 bits at a time whereas 64-bit processes 64 bit at atime...
Its like say there is a passage ..Through one passage 32 peoples can pass at the same time ...On the other hand there is a passage by which 64 peoples can go same time.

So 64 bit processes twice the speed than that of 32 bit

The terms 32-bit and 64-bit refer to the way CPU handles information. The 64-bit version of Windows handles large amounts of random access memory more effectively than a 32-bit system. Check this Microsoft article on a description of the differences between 32-bit versions of Windows Vista and 64-bit versions of Windows Vista