installing lingphone or any other voip phone working with linux

[machu pichu]

Hi,  First of all  THANKS in advance for the help.  Where I live people 
I ask have not even heard of linux.  Please tell me if I am here at the 
right address, if not, where do I go with my questions!

I am using ubuntu7.10  installed gutsy gibbon

With the previous operating system, the last one that came out !, I used 
Voipstunt phone. I have been unable to get an answer from them, if they 
serve ubuntu.
Now I found lingphone
       Which version do I need to download ?
       With what application do I open it ?
       How do I install it ?
May be you can  suggest another voip phone which is usable in Europe. 
just phone will do, no video needed.
There are various applets
       Which one do I need ?
       How do I install them?
Thank you, regards
M