Since he didn't come across any issues or bug reports, Richard Heyes has officially released his SMTP class for PHP5 as "out of public beta" and ready for production use.

I've not added any new features to the class; I've simply updated it to be, well, better. Plus it uses PHP5's object model better. It's really just an update, ie if you're using the old version and it works, then you have no real reason to update it.

You can check out the source here and an example of it in action here.