[outkafe] Install of outkafe on Kubuntu 8.04

Hi
I have just been trying to help someone install outkafe on Kubuntu8.04
Everything was fine apart from being unable to get libpq.so.4 - The last few 
versions of Kubuntu all install libpq5 by default but have had libpq4 
available but now I can not find this library or anything else in the 
repositories that contains libpq.so.4
Later versions (well 9.04 at least) also no longer have libpq4 available.
We tried to edit the setup script file to ignore missing dependencies so we 
could complete the install (found this suggestion on a google search) but the 
cafe client fails to run due to libpq.so.4 not being found.
Any idea where I can get this in a form installable on a currently supported 
version of Kubuntu?
Thanks
Peter