How to set up POP3 for Gmail using Windows Mail in Vista.
This is a continuation of the steps that you can see here:
In this first image, you can see that you want to put in the type of email server type and the URLs that will be utilized.

In the next step, you will want to put in your full gmail account, including @gmail.com and your password. "Remember password" is set on as default, you can shut it off if you please. It just makes it easier if it is set to remember.
The image below should be what your servers advanced tab should look like. This comes after you click next on the previous step. There is 1 window in there, but just click finish or OK to go on. Do NOT download the mail right now as it will not be able to connect. To get to the account properties, you will (on the main window) want to go to Tools -> Accounts, highlight your account (should be the first one up top) and choose properties on the right side. You will then proceed to the servers tab. The only step here is to just select "My server requires authentication."
This is the final step. To get here, on the properties, choose the advanced tab. Then make sure your click both of the "This server requires a secure connect (SSL)". The server port numbers should be the same as below.

You will notice that I selected "Leave a copy of messages on server", because I like to have my emails archived. You may/may not want to do this, but with Gmail and the almost unlimited space they provide, it won't hurt to save the emails.