Simple Single Sign On Portal

I require a simple single sign in page with 2 components that will allow a user to access information from different sites without having to log in to each individually. First page contains two sections: 1. "Sign-In" -Username + Password 2. "Join" -Click here to join -First -Last -Email Address -Etc. After a uses signs in or registers: "Add a Site" (details to follow) In this section, users add the sign in credentials for the sites they want to access using the portal. ----------------------------------- After a user signs up and adds their own site credentials, this page is to pull certain information from the sites and generate a consolidated report of the contents. When a user clicks on a link, the user will be taken to the site, already logged in.