In this new tutorial from Builder.com.au today, they seek to help you simplify the validation of email addresses with the help of a little PHP.

A very common task when building Web sites involves validating user-supplied e-mail addresses. This is of particular importance to sites which require a valid e-mail address for transactions -- e-commerce sites, Web mail sites, mailing lists and so on.

If your Web site uses PHP, however, you're in luck. It's extremely easy to validate user supplied e-mail addresses in PHP, thanks largely to a very powerful regular expression engine built into the language. In this article, I'll demonstrate how easy it is.

They choose the preg_* functions to make their matches, giving you the sample code and regular expression string to help you validate the most. They describe what the expression does, but don't look for an introduction to regular expressions here...