[BBLISA] Upgrading from RHEL5 32 to 64-bit?

[Scott Ehrlich]

Is there a way to check whether 32 or 64-bit RHEL5 was installed on a system? 
For that matter, any way to check 32 or 64-bit versions of any RedHat or 
Linux-based (including Debian/Ubuntu) system?

Next, if a user's system was installed with 32-bit RHEL5, is there a reasonable 
way to upgrade it to 64-bit?   Can the 64-bit CDs be installed and let them 
take over?   Does a fresh install need to be done?

Would the same hold true for Fedora, CentOS, etc?

Please advise.

Thanks.

Scott