Login Using Email and Password

How do I get the user to login using their EMAIL and PASSWORD, instead of Username and Password? I looked but can't find it.

Thanks!

I just realized that in the email that is sent to the user it shows the username as the email, which is what I want, but on the actual login page is says "Username". So I changed that to say "Email" in the language file. I think that will work.

Thanks!!