Organizations & Associations

American Numismatic Association
Money.org is the official website of the American Numismatic Association, which is full of useful information concerning coins, currency and other numismatic areas of interest.

The American Numismatic Society
The mission of The American Numismatic Society is to be the preeminent national institution advancing the study and appreciation of coins, medals and related objects of all cultures as historical and artistic documents, by maintaining the foremost numismatic collection and library, by supporting   scholarly research and publications, and by sponsoring educational and   interpretive programs for diverse audiences.

Society of Paper Money Collectors
Official website of The Society of Paper Money Collectors, Inc. Great paper money organization for anyone serious about collecting currency.

Professional Currency Dealers Association
This is the official website of the Professional Currency Dealers Association. From this website, you can obtain a list of all PCDA members, their address, phone numbers, web sites and areas of specialization.

Currency Grading Services

Paper Money Guaranty
Paper Money Guaranty (PMG) is an independent third-party paper money grading service that houses notes in semi-hard plastic holders.

PCGS - Coin Grading
Professional Coin Grading Service. 

PCGS - Currency Grading
The standard for paper money grading.

Currency Dealers

Ray Marrello's Antique Curreny
Specialized in rare U.S. currency this website offers a large selection of all types of old U.S. currency including large-size type notes, national bank notes, small-size notes, error notes, obsolete currency, colonial currency, Military Payment Certificates, fractional currency, star notes and high-denomination notes. 

Miscellaneous Coin Sites

CoinFacts.com
Online reference for U.S. coins.

The Bureau of Engraving and Printing
The Bureau of Engraving and Printing (BEP) is the largest producer of security documents in the United States.