Getting Started with Grails: The Acegi "expansion pack"
InfoQ recently published a step-by-step tutorial for quickly installing and configuring the Grails Acegi plugin into the Racetrack application (originally developed in Getting Started with Grails). Kudos to Fadi Shami for assembling this handy guide.
You can find out more about the Grails Acegi plugin and the rest of the fast-growing plugin ecosystem at the official Grails plugin site.