In current global market, it is more usual to have to implement an SAP solution across different countries. Here there are some useful links about globalization and localization in SAP:
SAP Globalization
Information about globalization.
https://service.sap.com/globalization
SAP Localization
Information about localization in SAP. It contains useful links.
https://service.sap.com/localization
SAP Legal Changes
Information about legal changes in SAP.
https://service.sap.com/legalchanges
SAP Country Legal Changes (CLC)
Legal Changes specific to SAP HCM.
https://service.sap.com/hrlegalchanges
SAP Country versions
Information about the Country versions available in SAP.
http://help.sap.com/erp2005_ehp_07/helpdata/en/5a/d34a9f544811d1895e0000e8323c4f/frameset.htm
SAP Globalization Knowledge Base
SAP GKB was replaced by SAP Localization > Countries.