The SMTP server, although previously included in IIS, wasn't supported by the IIS team. For whatever reason, the Microsoft owning team has decided to withdraw it from Vista, only including it with Server 2008.
Therefore you need a 3rd party product. A good and simple replacement is Free SMTP Server:
Free SMTP Server is a SMTP server
program for Windows that lets you send
email messages directly from your
computer. It's very simple but very
useful for laptop users traveling
around the world and connecting their
PCs to different Internet Service
Providers in different countries. You
can use it instead of ISP's SMTP
server to increase your security and
privacy. Free SMTP Server supports all
email programs like Outlook Express
and Eudora, but best optimized to work
with Outlook Express. The email
program you already use for sending
and receiving messages can be
connected to the server in a very easy
way - by using the word "localhost"
instead of your current SMTP host.
Having done so, you can send messages
in a usual manner. Free SMTP Server is
very fast, while sending, it
establishes dozens of SMTP
connections, and gets the most out of
your Internet connection. The user
interface of the program is very easy
to learn, excellent documentation is
included. The program is freeware so
there is no reason not to download and
try it!
