Printing Progress for DD

PV does everything.

root@mlll2664:~# pv -tpreb /dev/sdc | dd of=/dev/sdd bs=512M
27.5GB 0:03:28 [ 130MB/s] [========>                          ] 12% ETA 0:24:39

You can also funnel this into the dialog tool and make it visual:

HowTo: Check The Status of dd Command In Progress under Unix like operating systems

See here for more details.