Normally using Skype on your iPhone workes the same way it does on a PC/Mac. Meaning that Skype to Skype calls are free and that if you use Skype to make calls to phones (and not Skype clients on PC/Mac/iPhone/Android etc) you will need Skype credit to place those calls.
The main difference between using Skype on your phone (iPhone, Android, Symbian or whatever) vs your PC is that Skype on your phone will use data against your data plan you have with your cell-phone provider. When you use your PC, the data used by Skype is most likely to come from your broadband provider which usually have more or less unlimited plans.
If you plan to use Skype a lot (or any other App that uses data on your phone, like e-mail/Safari web browzing etc) you should make sure that you have a data plan with your cell phone provider. That way you will get a bucket of included data and depending on how much you use, you should not have to pay per bit/minute.
15-04-2013 10:40 - edited 15-04-2013 10:42
Skype-to-Skype calling is free on your device, just like it is on your computer. But if you call mobiles and landlines from the Skype application, you will need a little Skype Credit or a subscription.
To make a Skype-to-Skype call on your phone:
1- Sign in to Skype.
2- Select the Contacts tab.
3- Choose a contact from your contacts list and click on Call