Viber http://viber.com/ is available for Linux (64 bit) as a beta. It's a good cross-platform app which uses your phone number as its ID, so no need to mess about with accounts and adding friends and so on. Any contacts in your contact list that use Viber will automatically show up in the Viber dialler.
Popular Mobile IM / VoIP App `Viber` Available For Linux ~ Web Upd8: Ubuntu / Linux blog
I tried it on Ubuntu 12.04 and it seems to work well. The noise cancelling seems very good as I could hold a conversation using the laptop's built-in mic and speakers.Quote:
Earlier this month, Viber Media Inc. has released Viber for Linux as a public beta. For now, there are only 64bit binaries available for download.