Here's a form with which you can email me. Please be sure to input your actual email address and/or provide other valid contact info if you require a response.
If your message has file attachments or you'd just prefer to email me directly, send your email to rob at this domain. If you wish to use encryption, my public key can be found here.
If you wish to get in touch by means other than email, here are some more ways to contact me.