Probably the most extensively used resource in the music cataloging world, this page, put together by Michelle Koth at Yale University, provides a comprehensive resource for all aspects of music cataloging.

Though many of the included materials are specifically meant for Yale processes, many are useful to all catalogers. This list provides information for everything from call numbers to the names of instruments in many different languages, as well as links to many other resources that are helpful.

Three of the resources that I use most often from this site are the names of instruments in different languages, list of types of compositions for use in music uniform titles, and a handbook of examples for use in authority records by the NACO-Music Project.

Table of Contents:

Call numbers
Music cataloging resources
Authority control and NACO
Uniform titles
AACR2
MARC
Subject cataloging
Sound recording cataloging
OBRIS and OCLC
Language tools
Biographical sources
Bindery and marking
Other music cataloging sites
Online catalogs
New Grove, 2nd ed.
Yale staff resources
Online biographical sources at Yale
Hoaxes, viruses, scams and spam
Russian transliteration table
ISBN checker
Roman numeral converter

Internship notes:

Just keep swimming…