A. The production version of Exchange 2007 will run only on x64 type 64-bit processors (Intel Extended Memory 64-bit Technology--EM64T--or AMD64. Support for the Itanium (IA-64) processor isn't included.Clients don't have to be 64-bit to communicate with Exchange 2007.
Microsoft does have available 32-bit versions of Exchange 2007 for testing only. You can download a pre-created virtual hard drive (VHD) version that expires after 30 days hereor get the evaluation version here, which expires after 120 days and contains both a 64-bit and 32-bit version.