Identifying an exe for 32 bit and 64 bit

Folks,
I am looking for a utility or a method using which i can identify whether an executeable is built for 32 bit or 64 bit. For example:
In unix, 'file <exe-name>' would tell me whether the exe is a 32 bit one or a 64 bit. Is there any such utility for Windows?

I am currently porting a software from 32 bit to a 64 bit architecture and would like to know where it was originally built.

Thanks in advance,
viral.

http://support.microsoft.com/kb/913111
this might be useful to you