I want to create a "Sign up/Login" form exactly

Hi,

I want to create a "Sign up/Login" form exactly as in the edublogs.org (when I click login, I type username and passward to login). I want it in the top right of my home page. Which is the plugin to do that and how? I'm using multisite.

I attached a print of the screen when I'm not logged and after the login.

Thank you very much.