Here is a list of sites where you can download there mobile Java application.
Some cost money to chat in chat rooms well otheres are free
Enjoy (chatting takes up to much time)
Here are just some I can think of off hand.
MxIT - www.mxit.co.za/wap
2go - www.2go.co.za/wap
Jmirc - Mirc ( Java mobile IRC)
Do you've any others we can try out
I love chatting with my mobile phone.