  Acoustic neutrino detection is a promising technique to instrument the large
volumes required to measure the small expected flux of ultra-high energy
cosmogenic neutrinos. Using ice as detection medium allows for coincident
detection of neutrino interactions with acoustic sensors, radio antennas and
optical light sensors with the benefit of cross calibration possibilities or
independent measurements of the the same event. We review the past development
of the field and discuss its current status and challenges. Results from site
exploration studies, mainly by the South Pole Acoustic Test Setup (SPATS) which
has been codeployed with the IceCube neutrino telescope at South Pole, and
current physics results are presented. Current ideas for the design,
calibration, and deployment of acoustic sensors for new projects are shown. The
possible role of the acoustic technique in future in-ice neutrino detectors is
discussed.
