Hi, breezex, i checked on sipbroker, for MyNetPhone, but at the moment they do not peer good with other networks, which would be otherwise an option, to make free phone calls, since both "parties" have Voip on each end.
Another option is to call by sip-uri, you must know the username/number, plus de registar domain.
Or you and the callee, should have an account at the same (free) voip provider, and to make it more flexible, both parties should have the use of a Mysipswitch account,
You should tell some more about the hardware you are using, DECT-IP or an IP phone are devices easy to configure, and have less problems, because they are not ATA's ...
btw. Voxalot has also an australian .au server, this could be an advantage for your connection with Australia, and you could take an .eu account at Voxalot.
Thanks, The Fug.
gear: my ISP's Zyxel Modem/Router in bridge, Sitecom WL309 Router, Siemens Gigaset 301D