After the basic installation procedere, I had to perform the following steps additionally to keep everything happy and dump Emacs successfully. (I guess it has to do with some paths being left hard-coded in the port):
x:\tmp on the Emacs installation drive.
fns-20.6.1.el from x:\emacs\20.6\lib-src to x:\emacs\20.6\bin.
The readme.os2 files says rmail would work now. It did not for me and it gave me a hard time setting it up.
If your local pop3 mailbox is in Un*x format everything seems to be fine, but if you are using the lamailer format, retrieving mail from the local mailbox seems not to work. I always got the error message "Cannot convert to babyl format" when I tried to load the new mail with rmail. The problem is the movemail program which is distributed with Emacs and can be found in the x:\emacs\20.6\bin directory. After trying nearly every available pop3 mail retrieving program available for OS/2, I installed the old movemail program which is distributed with Emacs version 19.33 and the problem dissappeared immediately.
Make sure to install/replace the executable files in x:\emacs\20.6\bin.
Emacs has built-in context-sensitive help. Whenever the cursor is on an elisp variable or function name one can type [C-h v] or [C-h f] to get a description of the variable or function respectively. Emacs does so by relying on the TAGS files in the directories in which the elisp files (*.el) are stored.
Emacs 20.6 comes without TAGS files which means you will have to build those files yourself. This is done with the program etags which resides in the x:\emacs\20.6\bin directory.
When I tried to do just that, I always got an error message and nothing happened. When I used the etags program from the Emacs 19.33 distribution I was able to build all the TAGS files instantly.
However I still could not use context-sensitive help from within Emacs as everytime I typed [C-h v] or [C-h f] I got anoter error message related to the file fns-20.6.1.el in the x:\emacs\20.6\bin. It turned out that this files containes garbage at the very end. To solve the problem load it into Emacs and delete all the garbage.
You now have context-sensitive help available.
Download a working etags program. Put the files into the x:\emacs\20.6\bin directory. For your convenience I have included a batch file makeetags.cmd which will loop through all standard elisp directories to build the TAGS files. You must call this batch file from within the x:\emacs\20.6\bin for it to work properly.
Under construction: tm does not work out of the box, because it assumes Xemacs to be installed.