Buddypress is a great plugin, adding much more power to your website, but one of the things that really lets it down is the welcome email that is sent out and the lack of an easy way to edit it. You would normally have to go into the code and hard-code it, only to repeat the process when Buddypress is updated.
This is something that i wanted to do, and making a search on Google gave me various posts on WPMUdev, so I thought that it would be a good idea to let you know of a much easier way to do it.
Unfortunately, this is not a free option, as it involves buying a developer license for Gravity Forms, but if you don't mind doing that, then it will make life much easier and give your website a more professional touch. Of course, this is one plugin that WordPress developers should have at hand.
What you need to do, is install Gravity Forms and the User Registration plugin:
You then design the registration form as you want it to be for BuddyPress, including any of the profile fields that you have set up for Buddypress in the usual way. You should then select the notification options for your form, which will allow you to create the welcome email that your users will receive. Being Gravity Forms, this means that you can add information from the form that is filled in, so you can personalise it for each user.
Once you have done this, you should then click the User Registration link in the Gravity Forms section of your WordPress admin, and link the sections together, it's very straight forward and you can see exactly what you need to do. At the bottom of this options screen (as you can see below) is an option to send the password to the user, for the best result, you should uncheck this and just use the notification email for sending information.
This will not only make a nicer welcome email, but will also enable you to create a user registration form that is much better, you can have it spanning more than one page, only show sections that a user requires using conditional logic and, most importantly, look professional.