Index of the FreeDOS mailing list
Bootable FreeDOS a one-megabyte download for creating FreeDOS boot floppies
The Home Page of Pat Villani, the author of the FreeDOS kernel
Darwin
ReactOS Project -- A project to create a windows clone
GenWine a project to make a commercial Windows clone using the FreeBSD kernel with the Wine emulator running on top of it. While it is not quite open source, they plan to make all the source code available under a restricted license
The Windoze Replacement Project a project to create a windows clone running on a Linux Kernel with the Wine emulator
WinX, a planned shareware Windows NT clone
Freedows
Operating Systems Project Information
Download the BeOS Preview Release 2!
L3 and L4 Microkernel Operating Systems
The Mach 4 Project no longer developed by the University of Utah
New Deal Office A business-oriented operating system similar in spirit to Desqview and based on GEOS, it has multitasking and a GUI on IBM compatibles all the way back to the 286
Unix Linux