Since its invention in 1918, Soundex has become the de facto standard for phonetic searching. Microsoft SQL Server even has built-in support for phonetic matching via the SOUNDEX() and DIFFERENCE() functions. It comes as no surprise that modern users take advantage of Soundex functionality in a wide variety of applications including genealogy, customer relationship management, law enforcement and the growing field of anti-terrorism. In this article, Michael Coles demonstrates how to take advantage of Soundex in your own applications. He'll introduce you to the Microsoft-supplied Soundex function, discuss the differences between this and the NARA standard, and then work through a SQLCLR UDF that implements the NARA standard, thus allowing you to perform NARA-compliant queries directly from SQL Server 2005. The article also demonstrates how to use this feature from a web service or web application.