I hope most of here knows what’s Google411. Using Google 411 ( 1-800-466-4411) you can make free calls to any business listing in US and Canada. I just tried this application and called Dell and other business unit in US. To use this service all you need to skype application installed in your iPhone and you can call 1-800-466-4411 from your iPhone and follow the voice command to make free call from your iPhone.
They have complete business listing of US and Canada, in case if you not sure about the complete name of the business unit, you can take the first name and voice response will automatically give you the list of business unit with that name. This is fun and working trick.
Do let me know how you found this free iPhone call trick?