Pulling Exchange Global Address Book to use in ASP.NET

Ok, I am sure this is possible but after looking at Google and MSDN it
must
be well hidden!
>
In a company intranet ASP.NET app; the user needs to select email
addresses
to send copies of a report to. Rather than copy this data to a database
(where it can be out of date quickly...) I'd like to access user names and
email address from our Exchange 2003 server to populate a dropdown list.
>
Can anyon epoint me to a code example that shows such an approach that I
can
look at?
>
--
Thanks,
Dave Hamblin