Login into 3rd Party Website

I have an app, and I was wondering if it is possible to from this app login into the 3rd Party Site (it is not my site) with the user providing there username and password for that site, in a UITextField, and then send that data to the site? And have that user login, and then some of the user info of that user could be displayed in the app?

Thanks for the help in advance. I am new to accessing web and 3rd parties from app.