One of the best sites from the OECD is this one to lookup each country Exchange of Information Portal
The Exchange of Tax Information Portal is an initiative of the Global Forum on Transparency and Exchange of Information for Tax Purposes. The Global Forum conducts peer reviews of its member jurisdictions' ability to co-operate with other tax administrations in accordance with the internationally agreed standard. The standard provides for exchange of information on request where it is foreseeably relevant to the administration and enforcement of the domestic tax laws of the requesting jurisdiction. Effective exchange of information requires that jurisdictions ensure information is available, that it can be obtained by the tax authorities and that there are mechanisms in place allowing for the exchange of that information. The Global Forum's peer review process examines both the legal and regulatory aspects of exchange (Phase 1 reviews) and the exchange of information in practice (Phase 2). The EOI Portal will track the development of these peer reviews, including changes that jurisdiction's make in response to the Global Forum's recommendations.