Palringo (Android) - Palringo is a popular mobile group messaging service with a large active community of over 300,000 social groups. Send instant text, picture, and voice (Push-to-Talk) messages to friends, groups of friends, social groups, or anyone on any mobile device, PC, or Mac
Nimbuzz - Free messages, Free Calls. Unlimited!
Nimbuzz Messenger combines the power of internet and smart phone messenger into one, and lets you make cheap international voice calls, send unlimited chat messages, share files on any mobile device across popular messengers. Nimbuzz Messenger is available on Android, iOS, Blackberry, Symbian, Java, Windows and Mac
QIP Mobile Messenger (Android) - QIP Mobile is a mobile version of the popular messenger QIP, which is used by more than 20 million people in Russia and abroad.
Users can send each other messages via protocols: QIP, Jabber, Google Talk, Facebook, Vkontakte, LiveJournal, Yandex Online, Mail.ru Agent and ICQ