The current development version is available online. Please note that yhc is still not finished, so don't expect a full polished compiler yet!
There are two versions, the stable one and the development one. If you want to contribute to Yhc, we recommend the development one. At the moment, because development is so rapid, the stable version is usually quite out of date.
darcs get http://www.cs.york.ac.uk/fp/darcs/yhc darcs get http://www.cs.york.ac.uk/fp/darcs/yhc-devel
There is a mailing list for general discussion, bug reports etc.
There is also a blog, where development style posts are made. This is probably better for getting a feel of the project.
License & Copyright
Yhc is substantially based on nhc98, which is (C) Niklas Röjemo, 1991-1998. Many parts of the nhc98 compiler, libraries, and build system were contributed or modified by Malcolm Wallace, Jan Sparud, David Wakeling, Colin Runciman, Phil Hassall, Olaf Chitil, and Thomas Nordin, and are copyright to them, their respective institutions, or funding bodies, (C) 1996-2004.
Yhc is released under the GPL, but programs compiled with Yhc are free from additional copyright restrictions.