Need simple, secure PHP contact form

I can do it myself (and have done so) by kludging through my homemade n00b code and blending with borrowed, open source snippets. But what's really needed is something that's solid and reliably functional and trustworthy, without vulnerabilities.

Hopefully, there's a solution that's portable across sites/domains by defining/re-defining/adding variables and customizing form input fields accordingly.

You know the drill: Stickymail me here at WebmasterWorld if you can help.