An anonymous developer has released iOpener, an application which integrates DeDRMS and FairKeys with iTunes. From the FAQ:
iOpener is an application that will find all of the “protected” AAC files in your iTunes library (the ones you purchased online) and remove the DRM (encryption) from them “in place”, allowing you to enjoy the music you’ve purchased on any device anywhere that supports the standard AAC format. This means that you will notice no change whatsoever in iTunes except that the “type” of the track will change from “Protected AAC audio file” to “AAC audio file”. Additionally, iOpener can run in the background (in your task tray, actually) and auto-decrypt any “protected” AAC files as they are added to your iTunes library.