I know you can send the user their password using the forgot password form...but is it possible to send them their username as well?
Sure, from the admin panel go into a user's account, then select the "Actions" link (top of the screen, 3rd from the left) and click "Re-Send Signup Email"
If you are meaning can member retrieve username & password this is automatic if they enter their email address in 'forgotten password' box.
I currently have a form on my site where the user can enter their email and their password will be sent to their email, I was asking if I could also send them their username this way. This is the form that I have and it works for the password.
Strange because my form is the same as your and if member entere either username or password then the email they receive contains both username and password. Have you edited sendpass.php at all?