fring for Symbian 9.1 Fring gives you FREE video calls, voice calls and live chat to your fring buddies and to other friends on popular social networks: Google Talk, MSN Messenger, Yahoo!, AIM, ICQ, Twitter & SIP!
WhatsApp Messenger WhatsApp Messengeris a messaging app which allows you to exchange messages with your contacts without having to pay for SMS
XpressChat XpressChat allows you to chat with a random person
Octrotalk A Mobile Instant Messaging with voice and video integration
IMHere Free Yahoo/MSN(Windows Live Messenger) messenger
RockeTalk The free RockeTalk application provides a complete social media experience on the mobile handset with social networking, community creation and participation, media upload/download and posting/publishing to other mobiles as well as the web