The traditional request for legalization of documents used abroad required certification up the chain of line -- starting with the notary public (authenticating the document and signature), then moving on to the court clerk of the jurisdiction in which the notary public serves, and finally by the office of the state's secretary of state. The document would then have to be sent to the Authentication Office of the U.S. Department of State, where you would pay a nominal fee and tell them where the document was intended to be used, and the document would be authenticated for use abroad, and ultimately transmitted to the other state's embassy or consulate.
Luckily that process is rarely used anymore because most countries are members of the Hague Legalization Convention. For a list of members of the Convention, click here, http://www.hcch.net/index_en.php?act=conventions.status&cid=41 This Convention streamlines the procedure for international acceptance of document through use of a convention apostille. The apostille is appended to the document, and allows it to be accepted in other Hague Convention member country. When requesting a certifying body in the U.S. for an apostille for your document, you will have to advise them of the country in which you intend to use the document.
Where do I get an Apostille?
The Administrative Office of the Federal Courts issues apostilles for U.S. federal court documents.
Apostilles for state-issued documents can be obtained from the Secretary of State's office (notary office/document authentication office) in your state. Apostilles can be obtained for documents issued by state or local courts, birth/death/marriage records, documents issued by state or local government agencies, and documents signed before a notary public. Wills, powers of attorney, attestations, affidavits and other documents that have been sworn to before a notary public are all covered by the Hague Legalization Convention.
The Convention does not apply to commercial documents, such as a bill of lading, since those documents were not originally sworn to before a notary public, and did not otherwise undergo a certification process. Therefore, if you wish to have commercial documents authenticated for use outside of the U.S., you will need to follow the more onerous "traditional" procedure for legalization of documents.