How do I check if a process is running in 64 bit or 32 bit mode?

Question

I'd like to check if a process is running in 64 bit or 32 bit mode. How can I do this? Process Explorer will tell me if the Image is 32-bit or 64-bit, is this what I should be looking at?

Answer 1

Can we assume this is a windows question? xp x64, vista, 7 ??

In Windows 7 I believe a 32 bit application running in a 64 bit OS has a *32 after its name in the Task Manager...