What is a zip code of the republic of Georgia?

You don't say what country you live in, but I'm going to answer this as if you live in the US. This matters since first any mail must get out of your country and to the country in question. Here is a sample address for the Republic of Georgia:
Mikheil SAAKASHVILI <----Name
31 Rustaveli Avenue <----Street Address
0100 TBILISI <----Postcode City
GEORGIA <----Country

The ISO code for Georgia is GE, incidentally, and this is needed in some countries.

Based on the posting above, I did some additional research. The six digit postcode he cited will probably work, but is not the official post code. It is a hold over from the old Soviet Union postcode system. Please reference my second citation from the UN organization that manages international post.
You don't say what country you live in, but I'm going to answer this as if you live in the US. This matters since first any mail must get out of your country and to the country in question. Here is a sample address for the Republic of Georgia:
Mikheil SAAKASHVILI <----Name
31 Rustaveli Avenue <----Street Address
0100 TBILISI <----Postcode City
GEORGIA <----Country

The ISO code for Georgia is GE, incidentally, and this is needed in some countries.

Based on the posting above, I did some additional research. The six digit postcode he cited will probably work, but is not the official post code. It is a hold over from the old Soviet Union postcode system. Please reference my second citation from the UN organization that manages international post.