I am creating a web-page/website that integrates all my accounts into one spectrum, as in, from this page I want to use this page to log into my mail box online or any other site that requires authentication. All i want is a central login panel. enter my unname&passwd and get redirected to my mail. Is that an impossible question to ask?
It completely depends on the individual service. You'll have to investigate each service to see if they even allow you to authenticate against their servers remotely. In the event that they do allow it, it's still up to the service whether or not you'll be able to retrieve any kind of information from them after logging in.
Banks in particular are very unlikely to give you any way to interface with them and the ones that do will likely require a monthly access fee.