There's a really nice VoIP Security article on the ITObserver today.

VoIP Security
By Ray Stanton and Andy Hodgson, BT
Wednesday, 16 August 2006 01:25 EST

There’s no doubt that Voice over IP (VoIP) is the future of telephony. What started as a rather cumbersome way for budget-conscious enthusiasts to talk to each other using their computers has now developed into something of much greater significance – IP telephony, a new way of delivering fully-featured phone services that promises big cost savings and opens the way for a whole new range of multimedia communication services.

The new technology promises significant benefits. Organisations save by eliminating the need to operate separate voice and data networks to connect their employees and facilities, for example. They can also improve their efficiency and flexibility. IP phones aren’t constrained by the need for a dedicated line back to an exchange. This removes the ties between phone numbers and the phones themselves – numbers can instead be allocated to people and associated with whichever phone the user chooses to log in to, wherever on the corporate network that might be. This not only makes flexible working much easier, it creates new opportunities when it comes to the allocation of work to employees. Where IP telephony is used, anyone can log in to take calls to the call centre, for example – not just those in the call centre itself.