NSLU2 + Asterisk + Voipbuster account + USB phone how to?

Hello

can someone explain how can I perform this?
which tutorial should I follow?

I want to install Asterisk and use my voipbuster account to make phone
calls with a Premier Noblesse USB phone.

I want this to avoid having a computer always on just to make phone
calls. (the phone connects with the software that came with it where I
need to configure my Voipbuster account)

thank you