I've become sidetracked. MySQL is on hold because after playing with Apache I got interested in setting up a mailserver on my laptop, especially since BT Broadband do not offer an SMTP service. I had been testing SpyMac's free SMTP but it doesn't always allow me access if I haven't checked my SpyMac mail recently.
However there is a solution - sending mail with my own SMTP server and not relying on any ISP. Prior to version 10.3 OS X came with sendmail installed but disabled; it now ships with Postfix installed but disabled. So I needed to enable Postfix. Graham Ordorff covers OS X and mail servering (including Postfix) in intricate detail here, whilst John Brewer has written a slick tutorial here concentrating on setting up Postfix with authentication. Reading through these two tutorials enabled me to get Postfix up and running for my outgoing mail. For incoming mail I still rely on Fastmail's excellent free service.
Update: since getting Postfix working I've discovered (via FreshGoo) that the easiest solution may be Postfix Enabler which is available here on Bernard Teo's excellent weblog (he also has a Sendmail Enabler for pre-10.3 installations).