Had a bit of a break from posting while I have been travelling with work. Back now and so should be posting a bit more regularly.
Found this great presentation today on Slideshare by Manuel Lemos of PHPClasses.org:
“Sending E-mail that reaches the destination using PHP”.
It provides a basic overview of email protocols and systems and covers best practices to ensure email gets through, including specific reference to PHP classes he wrote. The MIME Email Message Sending PHP Class is really useful.