If we're not using Secure MIME (S/MIME), should we let users download the Microsoft Office Outlook Web Access (OWA) 2003 S/MIME control?

Absolutely! When you install the OWA 2003 S/MIME control on a client workstation, OWA 2003 gains some useful new abilities. My favorite is that the paperclip icon for attaching files opens the standard Windows Open File dialog box, which lets you attach files just as you would with Outlook. The control also lets you drag items (e.g., messages between folders, existing messages into new messages, files from Windows Explorer to a new message). You can also right-click an attachment to open, remove, or save that attachment from the context menu. And as a bonus, you can use any font when you compose a Rich Text Format (RTF) or HTML message. Because users can't do anything harmful with the OWA 2003 S/MIME control, no good reason exists for users not to use it.