Just want to comment for the nonSkype users: Skype to skype is free. Period. Skype to landline/cellphone etc are not free. You need to buy some subscription, like dial out credit or monthly credit $7.99/month, no contract, start and stop anytime you want to. There is a caveate though, for skype calling cellphone. Your skype on monthly subscription has practically unlimited minute, but you still burning cellphone minute on the cellphone you are calling to.
This is quite different for those cellphone that has family plan, that there is no limits when cellphone calling within family.

bun