The admin options will only show the components installed on your server that Snitz currently supports. A mail component is simply a way of allowing your scripts to "talk" to your server - e.g., I have an IMail mail server but use the (unrelated) JMail component to send e-mails with ASP - so you can select either one of those (I'd recommend CDONTS, but it's up to you) and then enter your server information accordingly.
Have a search of this forum as well; if I remember, there've been a few issues with authentication on Exchange servers.
Search is your friend “I was having a mildly paranoid day, mostly due to the fact that the mad priest lady from over the river had taken to nailing weasels to my front door again.”