Bulk sending of personalized e-mails from a database

Here's what happens: I have script that generates thousands of personalised e-mails and temporarily stores them in a database. Every e-mail is different. Note: this is not spam, I'm sending opt-in personalised newsletters. - Table: email_queue - Fields: recipient (email varchar), subject, html_body, date_sent (datetime), status The script should get the contents from the email_queue and send the e-mail one by one. Requirements: - Should use a smtp socket - Should be able to send fast, possibly connect to the smtp once and send 1.000 emails at a time - The e-mails must have the right headers, so they are not considered spam - Mark a message as 'sent' (date_sent) when it's done - Write the right status (1=delivered, 2=email does not exist, 3=mailbox full, etc) - Must use MySQL and PHP only I will add a cron job to activate the script and send relatively small amounts every ten minutes, so Hotmail / Gmail servers don't consider it spam because of the volume delivered from the same server.