How do you monitor the progress of dd?

dd is a wonder. It lets you duplicate a hard drive to another, completely zero a hard drive, etc. But once you launch a dd command, there's nothing to tell you of its progress. It just sits there at the cursor until the command finally finishes. So how does one monitor dd's progress?

[leechael]

dd if=... of=... bs=4M status=progress oflag=dsync