I’ve been using FREE-411 for the directory listing services, it seems Google has jumped into the Free Directory listing service (1-800-GOOG-411).

Google 411: 1-800-466-4411 (1800 GOOG 411) - free connect, no ads
Tellme 411: 1-800-555-8355 (1800 555 TELL) - ads
Free 411 : 1-800-373-3411 (1800 FREE 411) - no free connect, 10 sec ads

Check my old post for other phone based Free (useful) Services