a) apt-get install libqxmpp-dev psi ejabberd

b) edit /etc/ejabberd/ejabberd.cfg to allow inband registration:

   --8<---
   %% No username can be registered via in-band registration:
   %% To enable in-band registration, replace 'deny' with 'allow'
   % (note that if you remove mod_register from modules list then users will not
   % be able to change their password as well as register).
   % This setting is default because it's more safe.
   {access, register, [{allow, all}]}.
   --8<---

c) start psi and configure it to use 'localhost' as server and create two
    accounts: <yourname>:<yourpass>
              qtapp:test

d) login with <yourname> and qtapp, add both accounts to their contact list,
    and try to send messages. logoff the qtapp account.

e) build the qt client application and start it:

qmake
make
./client

f) the qtapp account needs now to be online in psi, write a messagte to qtapp
    the message should be displayed in the commandline