IMPORTING FROM Z39.50 SERVER WITH Character Set: win1250 (ISO 6937/2) into KOHA-2.0 WITH UTF-8 

Files from this directory are here as a fix only and are of temporary nature. The fix was delivered to me by Zbigniew Bomart.
It will probably work for the Polish Language only. The issue needs to be addressed by Koha developers for the general audience.
There's a general problem with z39.50 import feature for koha instalations whose default charset IS NOT iso-8859-1.
When importing from z39.50 servers that keep their records in windows-1250 charset encoding and koha installation with UTF-8 one may use the replacement files in this directory. 
Copy them to the following location:
/usr/local/koha/intranet/modules/C4/Biblio.pm
/usr/local/koha/intranet/cgi-bin/z3950/search.pl

and enjoy importing records in UTF-8 from Character Set: win1250 (ISO 6937/2) servers.
I tested it and the files seem to work on Fedora Core 1 and Koha-2.0

Remember to set the appropriate permissions on the files once you copy them. On my machine it is:
-rwxr-xr-x    1 apache   apache      91813 May  2 18:34 Biblio.pm
-rwxr-xr-x    1 apache   apache       3263 May  2 18:39 search.pl

Benedict P. Barszcz