email system

i have searched all over the internet mainly looking for some sort of email script so members who log into my site can get a message from other users but the way i wan't this to work is by a database the database holds all the info so a user can send a message to another user just by typing in there name, its more or less like hotmail except it is only for the members and no one else is this possible possible and if so does anyone know were i can get this script or tutorial on how to make somthing simular to it and i will try to edit it from there.

try http://www.hotscripts.com i had a nice mail script from there!

ok i will thanks