IM+ Talk for symbian 5th edition such as Nokia 5800 or N97 allows you can chat with Skype friends, call any PC, mobile phone, making it very cost effective and it does not need WiFi and works on all carriers networks as well
IMHere-
By far the most advanced Yahoo/MSN messenger for mobiles. This new version integrates Google Maps. Now you can see where you and your buddies are
IM+ Talk- enables voice and text communication with other Skype users and provides cost-effective calling to landlines and mobiles.
Call Skype users to their PCs. With IM+ Talk you can talk with other Skype users all over the world.
Make cost-effective calls to any destination
SMS Chat is the new complete SMS messenger for your Nokia S60 phone. With SMS Chat you can send and read SMS messages in more fun, easy and convenient way
mIRGGI is the first IRC client for S60 3rd Edition devices. It is currently in early stages because I just began writing it on 10th of March. I've been meaning to do this for a long time but haven't gotten to it. I don't like the J2ME IRC clients (one big reason is that they suck up a lot of memory on S60) and I don't like using PuTTY, especially on devices without keyboard
fring v 3.40.19 is a mobile internet service & community that enables you to access & interact with your social networks on-the-go, make free calls and live chat with all your fring, Skype, MSN Messenger, Google Talk, ICQ, SIP, Twitter, Yahoo! and AIM friends using your handset’s internet connection
IM+ for Skype® enables voice and text communication with other Skype users and provides cost-effective calling to landlines and mobiles.
Call Skype users to their PCs. With IM+ for Skype you can talk with other Skype users all over the world.
Make cost-effective calls to any destination
IMChat- an Instant Messenger java application for mobile phones that works with MSN messenger.
# Messages can be sent to other peoples mobiles using GPRS at a cheaper cost than sending SMS messages.
# (You just pay for the GPRS connection and data transfer rates set by your mobile Operator
