See:
http://www.sean-barton.co.uk/2009/04/welcome-email-editor-for-wordpress/
If you really, really want to BCC the additional recipients, just add them in the “extra headers” field, e.g.:
BCC: fictitious@example.com,invented@test.net
One important point though: keep in mind that you’re sending login info (user + pass) over email out to others than the user him/herself!
So, if your intent is to JUST send copies out of the admin notification (just to notify of a new user with his/her email address) you’ll have to tweak the code. See the author, e.g. at the link I just posted, above.
But I digress: I agree, it’s an awesome plugin.
Hey thanks for the feedback. BCC is the easiest way to do things as nv1962 has suggested. Let me know if this works out for you.
thanks
Sean