Skype charges a flat rate as of 1/1/2007 of $29.95 for unlimited to call to Canada and the U.S. Yes you can use it to call other Skype customers but Skype has less than half the features of Vonage. Not to mention Vonage just released Vonage Talk which is a free call software to any Vonage customer or any Vonage Talk user anywhere in the world.
The international rates of Skype are not 2 cents/minute to most locations they are well over 50 cents a minute to a lot of places. They are 2 cents/minute to the UK which Vonage includes in their calling plans not to mention that Spain, Italy, Ireland, France, Puerto Rico, and Canada are also included in their free calling area of their plans.
Also the Vonage talk software works as an IM chat. Allowing me to chat for free with anyone.
Why would I use Skype, when Vonage is better on all fronts at this point?