VoIP Test Configuration

[Mihai Amarandei <mihai () xmcopartners com>]

Hi,
I'm a student doing some resarch on VoIP security. I'd like to implement 
a small VoIP virtual network (vmware maybe) to be able to study a real 
VoIP network, and not just whitepapers.
Does anyone here have somme suggestion as to which tools/products to use 
and in which config?
Tx
Mihai