http://www.devel.lyx.org/download/
Jean-Marc, this link (to the LyX on OSX (X11) HOWTO) now goes to lyx_on_aqua.html. I guess that that makes the paragraph redundant. Angus Beside the page mentioned above, Ronald Florence has also set up a LyX on OSX (X11) HOWTO for installing LyX on Mac OS X, either with the xforms or the Qt interface (you will need an X window server in both cases). This page also outlines procedures for integrating LyX into the Mac OS X drag-and-drop and double-click interface.