With -
COM (using Outlook)

Under Outlook XP or greater, you will get security warnings about the program trying to send a message on your behalf.

Two ways to get around this:
(1) Download ClickYes - It will not work if the machine locks, but will if you unlock it. Also, look at the example code displayed on the site to use this.
(2) Review this document - However, it appears to have some limitations.

{Editor's note - Thanks Lonkero!}
is not fully correct.
we use office 2k sr-1 sp3 and it gives the same warnings.

Utilize these resources:
UDFs (Full List)
KiXtart FAQ & How to's