I would like to move a git repo I have to darcs. I have not been able to find docs or projects that explain how to do this; it looks like most users want to go the other way. In
darcs-fastconvert has been updated to version 0.2 : http://lists.osuosl.org/pipermail/darcs-users/2010-November/025670.html I think this now is the safest way to do git <-> darcs bridging.
I'd like to add to gh_'s answer. darcs-bridge (formerly darcs-fastconvert) also uses the fast-export format. It is built on the Darcs library (by a darcs developer) and can be installed via cabal. It also supports marks file, which if I understand correctly, would allow for incremental conversion.
EDIT darcs-fastconvert has been superseded by the Darcs bridge. I've updated the link