The University of Washington's IMAP toolkit includes POP2, POP3 and IMAP servers that I've compiled for OS/2. The binary packages are widely available from Hobbes and its mirrors.
uwim200.zip(1.1M) -- University of Washington mail server executables [Australia] [Poland] [Sweden] [USA]
emxrt.zip(549k) -- EMX 0.9d run-time libraries [Australia] [Poland] [Sweden] [USA]
More details about installation and use of the mail servers can be found in the UWIMAPD.OS2 file packaged with the distribution.
The documentation in the distribution gives some very terse instructions on setting up mailboxes for users. Gabriele Gamba has provided some more friendly instructions at Netlabs.
Last edited: 11 September 2008