To use GOOG-411 just dial 1-800-466-4411 (aka 800-GOOG-411) and listen to the voice prompts. As part of a promotion for GOOG-411 leaving beta, Google said they will unveil which Googler is the voice behind GOOG-411.
Here is the video that announces GOOG-411′s graduation from Google Labs:
Google launched GOOG-411 back on April 6, 2007. And Greg Sterling had a nice post named Goog411 Voice Search and Speech Recognition. You can read our archives for more on Google Voice Search, plus checkout the Google Groups forum for goog411 if you have additional questions.