Yes, you can do this using a command like follows (this is almost straight from teh manual as well :-)
mail("sendto_address@someplace.com, "subject string", "mesage, \nwith some new lines", "CC: address_to_cc@someplace.com\nBCC: address1_to_bcc@someplace.com, address2_to_bcc@someplace.com");
only thing is to make sure by testing that it actually works, some versions of php have had bugs with this last part and it won't work.