These three countries plus Switzerland form the European Free Trade Area (EFTA) - see http://www.efta.int
Wikipedia notes at http://en.wikipedia.org/wiki/European_Economic_Area that:
- It was established at the start of 1994 following an agreement between the member states of the European Free Trade Association (EFTA) and the European Community (which became the EU). It allows the EFTA-EEA states to participate in the EU's Internal Market without being members of the EU. They adopt almost all EU legislation related to the single market, except laws on agriculture and fisheries. However they also contribute to and influence the formation of new EEA relevant policies and legislation at an early stage as part of a formal decision-shaping process. In addition, independence and direct membership of international bodies in their own right means the countries are able to participate in and become signatories to various conventions, such as the Basel Convention of 1992, that are only adopted by the EU many years later (2007).
One EFTA member, Switzerland, has not joined the EEA, but has a similar agreement with the EU.
There is a POERUP country report on one EFTA country, Norway
There are more EEA countries also reported on, using information from other projects and from volunteers - see Countries for an index to the full list. Virtually every country in the world has at least a small entry on POERUP.