Asus P5B - Manual (Page 25)

ASUS TeleSky User Manual 
Once installed Skype™ and Telecom Adapter Card Software,
when you log in to skype, a prompt appears. Select Allow
this program to use Skype and click OK.
Topping Up Your Account
In order to use the Skype out function and make calls to
other landline or mobile numbers, you must first purchase
calling credit through the Skype website.
The Skype log in page will appear in your browser. Enter
your username and password. The Your account page will
load. You can top up your credit from here.