Zoiper Mobile: SIP Softphone for windows smart phones WM5 WM6 WM7: a Fring alternative

Zoiper, one of the SIP/IAX softphone developer for Windows OS, Mac, Linux, Solaris have recently released SIP softphone for Windows mobile users. This is a good news for the windows mobile fans looking for Fring or Nimbuzz alternative

Linphone SIP software for Ubuntu Linux XP Vista and Mac : free VoIP video-phone

Linphone is an open source free SIP softphone, video phone which works with major operating systems like Ubuntu Linux XP Vista and Mac and allow you to register multiple SIP accounts with single sip software.