I rang my brothers telephone at Christmas time for Christmas 2006 and spent an hour and a half on the phone from Skype to his landline in Australia.
It cost me a grand total of about £0.35 or something, and it was as clear as a normal phone call!!
But then again, I've got a proper USB Skype phone to plug in to my computer... and when I'm not there my skype diverts to my mobile, I've also got a skype-in number in Australia

Also got a SKYPE mobile.. so people can call me free on the go! And I can call their computers or skype mobiles for free as well!!!! (if anyone else has one of these then let me know)
If you want my skype details you have to PM me tho.. Got two skype accounts, one for computer one for mobile.