Of course, that's the whole point! With the VoIPtalk service, you can:
Call other VoIPtalk users for free by dialling their VoIPtalk ID
In addition, using SIP, you can dial someone else using their SIP Address, for example: email@example.com. Note: This may not be applicable on particular phones or networks
With H323 or SIP, you can dial another user by dialling their IP Address. This is referred to as peer-to-peer communication. Note: This may not be applicable on particular phones or networks.