I’ve blogged about switching to Ekiga for PC to PC calls. I have still been using skype for US calls though. Not anymore. There might be many SIP service providers, but they seemed expensive to me. One of the cheaper ones is Gizmo. They have their own free beer client, but also provide a SIP proxy.
To get a call credit you can use with Ekiga, I:
Downloaded the Gizmo client and created an account.
Launched Ekiga and filled in the account info (edit>accounts):
Account Name: Gizmo, Registrar proxy01.sipphone.com:5060, User: SIP#, Password: GizmoPWD. The SIP# can be found in your profile page in the Gizmo client. There are additional entries in ‘More Options’:
Authentication Login: SIP#, Realm/Domain: proxy01.sipphone.com
Selected GSM as the preferred audio codec in Ekiga’s preferences. Speex was selected by default and didn’t work for me when I tested it with a landline.
Bought some credit. At $0.02/minute for US calls, this is going to last a while :)
Note that you get a little credit when you create an account, so you have an option to test things out before you buy. Also there seem to be no problems with dial tone based PIN entry as with Skype. The disadvantage of using Ekiga and not their client is that you don’t see how much credit you got left.