We've noticed a good deal of confusion surrounding the term "royalty free music" as it applies to music licensing and using background music in your media production.
Basically, a royalty free music license bundles a song's "synchronization rights" (the right to use the music composition in your production) and its "master-use rights" (the right to use the specific recording in your production) into one legal agreement so you can quickly and legally add it as background music in your media production.
The articles below discuss royalty free music licensing in further detail.
Royalty Free Music
How to use music legally in your work
Why I dislike the term "royalty free music"
Stock Music Licensing Explained
Royalty Free Music Explained
The Public Domain: A Guide for Media Producers
Royalty Free Classical Music
Royalty Free Classical Music - Best Practices
Royalty Free Classical Music: Vivaldi's Four Seasons
Copyright & Music Licensing
Music Clearance & Music Licensing
Copyright: The Basics
Music Licensing: Licensing Your Work
For Educators
Podcasting In The Classroom
Podcasting Production Tools
Digital Storytelling In The Classroom
Digital Video Tools for Schools
Using Background Music
How to best use background music in your production
How to create background music for the Horror Film Genre
Royalty Free Piano Music: Piano Solos for Production Music
Royalty Free Jazz & Lounge Music: 1960s Kitsch as a Game Soundtrack
Video Production
Video Production - How to Produce a Dynamite Demo Tape
Video Production: Vimeo, The Cadillac of Online Video
Background Music for Advertising
Where Have All the Jingles Gone?
Under the Influence: Advertising and Pop Music