There would be no additional charges for you as you are calling a US number.
There WOULD be additional charges for your friend, though as they are using a service provided by a foreign country. They can determine the additional charges by signing up for global services thru Verizon. Also, they would need to determine if their phone was capable of operating in a foreign country.
Currently, I believe it is a $0.89/minute charge for using a Verizon phone in Canada.