A major mode for editing programs in the D Programming Language. D is a modern replacement for C which attempts to rectify the mistakes made by C++ and Java.
The current version of the d-mode, compatible with Emacs23 and Emacs24, can be found at its development page at Github.
An older incarnation of d-mode, based on cc-mode 5.28, can be downloaded here. This version works on Emacs21, but does not work on Emacs22 (because Emacs22 comes with cc-mode 5.31).