Please post to the "Gretl-users" mailing list the following question:

I have easily weighted data in SPSS in the past, and now I would like to weight European Social Survey (ESS) data in the GRETL software package, if possible, but I don't know how. I would be most grateful if you advised me.

The syntax I use in SPSS for this purpose is as follows:
WEIGHT BY analysisweight .

Best Regards,
Evangelos Bekiaris PhD candidate 
University of Peloponnese