It's a pleasure to help. Having said my piece, I do use Skype, but only rarely, as it isn't very convenient for me: at the very least a mic is required by both parties and the PC needs to be on all the time for people to call (unless you prearrange a calling time). However, some routers are available that can handle VOIP with dedicated hardware, obviating the need to have the PC on all the time.
That said, it is a useful tool for those you want to stay in touch, especially with folk who live abroad, and don't want to rack up a large 'phone bill. I don't see much harm (unless you are with RMS on software freedoms) in trying it out for the purposes of getting the hang of using VOIP, then moving to another provider once you know what is what. However, your daughter may be reluctant to change to a different VOIP provider once you have a working solution in place (if she is not a techie) and that if you use your old Skype account again, the Australian leg of the family will see when you are logged into Skype if that account is still on their contacts list. Also, I can't speak for Ubuntu (I see that is what you are using), but on openSUSE: if you are using the 64 bit version of the distro, you need to locate a handful of 32 bit dependencies that don't get pulled in automatically upon installation of the rpm downloaded from www.skype.com
. This is a mild pain but internet forums and HOWTOs on your distros web pages will help here.
In your situation, I'd ask a techie friend or someone from your local LUG to help you experiment (if only to make and test the connection) with setting up either Skype or Sip Gate. I don't know if Sip Gate has a client but I think as it uses open protocols, a programme such as Linphone may act a client. It's great to pilot something first before rolling it out. Good luck.