http://groups.yahoo.com/group/osfree
http://groups.yahoo.com/group/freeostwo discussion groups about a replacement (for all of or part of) OS/2.
http://www.osfree.org (IIRC on the url).
http://sourceforge.net/projects/nudawn
an open source version of OS/2.
http://sourceforge.net/projects/reactos
an open source replacement for WinNT that will include being able to run OS/2.
BigWarpGuy
PS FreeDOS ( http://www.freedos.org ) that can be used to replace/update the 'mdos' part of OS/2 (?).
OS/2 Warp-ed to the very end.