Setting up an SMTP Server

Here's our situation, and we have no idea how to set it up.

We have a web server, runing ASP.NET pages. We want to set up an SMTP server so we can send e-mails.

Here's the problem. We only want the server to be able to use the SMTP server, so nobody else will use it to bounce spam across the world. We'll assume the server's Computer Name is WEB and IP address is 10.0.0.1.

We don't want to have to log-in, and we want to be able to send to any e-mail address from any sender. But we only want the server to be able to do this.

How do we set this up in IIS 6.0?

I don't have IIS6. If it's like IIS5, you do the SMTP configuration from the IIS MMC and there is online help available there.