Per this reference @ Microsoft:
I should be able to set the date / time format for all utilities in one place.
Seems only partially true. I was able to at least get 24-hour.
Here's what the time format control panel states:
Here's what I see in outlook which is sort of a blend of long and short formats, but not precisely what I've asked for, where did the ":" come from in the time stamp - I didn't ask for that?!?!?!?. Let's see if W7 is any better - kind of doubt it.