[asterisk-users] Asterisk with VoIP phone

[J Rangi]

Hello,

Is is possible to setup an asterisk server with out buying Digium card. 
I mean can we do this type of setup.
We all know that X-Lite can be used as a soft phone to have an IP 
extension.
Is it possible to take a service from another VoIP service provider, and 
get the IP phone number. Make that phone numbe gateway to outside world. 
Now all the internal extensions use that phone to receive and make calls 
to out side world.
Has any one done this kind of setup or know anything about this.

Thank you,
-Jai