After featuring Skype's version 1.4 beta, it is time that we feature a SIP-compliant VoIP softphone also. The OpenWengo project releases version 2.1 of its WengoPhone softphone. Improvements over the previous version includes interoperability (support for openSER and Asterisk), security (AES128 encryption) and more language support. Drop by the website to learn about the other improvements and features.

Linux.com's Nathan Willis gives a first look review of WengoPhone 2.1 and concludes "

(O)n the other hand, WengoPhone 2.1 is hands-down a better option for cross-platform VoIP calls than proprietary applications like Skype and Gizmo Project. The Linux build is a big step up from the previous 2.0-RC releases. If you need to set up a VoIP call to someone on another operating system, give WengoPhone a try."

Hmmm, is it time for me to dump GizmoProject?