WSS: Error message "Can not add the user because a user with that name already exists."

So you've added a user in AD, then subsequently deleted the user, and eventually re-added someone with the same user name. Everything works, except when you go to WSS (Windows Sharepoint Services) to add the user to a site you receive the following error: "Can not add the user because a user with that name already exists.", what do you do?

You have to remove the original account from the Site collection, and then just re-add them to the site you need them to have access to.

To do so, from the WSS web interface perform the following steps:
1) Click "Site Settings",
2) Click "Site Administration",
3) Click "View Site Collection User Information"
4) Find the user in question and remove him/her.
5) Add the user to the site in question.