Your Username And Password email

I'm trying to find out how to change an email created likely by buddypress or the membership plugin.

This email arrives as soon as someone joins and says.

From: noreply@sitename.com

Subject: [Site Name] Your username and password

The body simply says
Username: user
Password: password
http://sitename.com/wp-login.php

I don't really want people to login on that page, and I want to give a better welcome email. Any ideas where to find this?

I tried /wp-admin/network/settings.php
However, the emails in that are not what is above.

- Tony