question about setting email parameters

Can somebody explain how to add multiple TO:, CC:, and BCC: recipients to an email in PHP? All the examples I've been able to dig up are too trivial (one recipient, short message); the best they say is to just past everything together. I tried that with a TO and a BCC and got two messages at the first address. For example, how would one prepare headers for something like the following: To: john@abc.com, bill@def.net, sam.sneed@xyz.aaa.com CC: sue@aol.com, tim@billsplace.com BCC: tom@billandted.com, cindy@anotherone.com From: joe@joesplace.org ReplyTo: jumpnjoe@edsdiner.com Subject: today's meeting Message: we had a really great meeting today! Wish you were here. -joe Thanks -David