When using IIS7 and vista you may find yourself without a local smtp server.
To get around that there are a few free smtp services you can use.
Free SMTP Server
http://softstack.com/freesmtp.html
Smartermail - Free for one domain.
http://www.smartertools.com/Products/SmarterMail/Free.aspx
both are a bit difficult to use (free one is an app) the smartermail is a full blown server solution.