VoIP2Go highly recommend the use of Zoiper softphones and phone App's with our VoIP Phone Service. It is by far the most powerful and feature rich VoIP software we have tested to date and it just keeps getting better.
You can download Zoiper pre-configured with the basic VoIP2Go settings from here or purchase one of the paid versions from their web site. There is a version available for all popular computers and smart phones and you can use all of them at the same time with VoIP2Go.
Once downloaded and installed, you will need to enter your Username and Password, which you receive when you sign up with VoIP2Go. You do this under, Preferences SIP Account Options. Also, enter your VoIP2Go Username into the Auth Username field under Outbound Options. In order to take full advantage of VoIP2Go network redundancy, you need to enable DNS SRV.