BuddyPress.org

Hi,
i would like to change the registration text. when a user register online, he will get this kind of message:
“You have successfully created your account! To begin using this site you will need to activate your account via the email we have just sent to your address.”
any idea how to change it, make the text bigger, maybe add a picture, or video?

moreover when you register you got email where you can find the link to validate your account, how could i change this email and make it nicer ?

thanks a lot,

cheers,
christophe,