How to setup Dynamic DNS (DDNS)

What is Dynamic DNS (DDNS)?

Dynamic DNS allows you to create a hostname that points to your home or office dynamic IP address, providing an easy-to-remember URL for quick access. Example usage includes providing the ability to send downloads to a TurnKey Torrent Server via the Torrent Server Handler Firefox extension remotely, or by accessing its web interface to checkup on downloads status.

Update: See TurnKey Domain management and Dynamic DNS &/or HubDNS docs