Email form checking for @

This question has probably been asked and answered before, but is simply unsearchable.

Here goes.

Making a flash/PHP email form, and I want to verify that the email address entered at least has an “@” in it. I’ve got a function that’s checking all text fields for text before allowing the email to be sent, but I just want the “email” field to verify it has a “@” in it before going through.

What’s the easiest way to do this?

Thanks advance,
-BLL