YMTiny

YMTiny is a free chat application supporting J2ME Yahoo! Messenger which directly connects to the Yahoo’s server. you just need your Yahoo! ID, and no other registration is needed.
works MIDP 2.0 mobile phones.

YMTyni has some features:

1. Settable message alerts: sound (midi), vibrate, flash backlight, open IM window
Bitmap fonts for consistent GUI
2. “Smart Ping” maintains connection and minimizes bandwidth usage
3. Receives offline messages, new mail and typing notifications
4. Set status and custom status
5. View a friend’s status, show and hide offline friends
6. Send and receive BUZZ!!!
7. Run in background and auto-restore
8. Window and scroll animations
9. Stylus support
10. 54+2 Emoticons!
11. Data counter

hoewever, this application has some limitations:

a. Does not support HTTP/WAP connection yet
b. Minimize function only works on some devices
c. Bitmap fonts could be invisible on some devices. Requires devices that support transparancy drawing.
d. Emoticons only works on bitmap fonts. Goto the Settings to change font.
e. Data counter may be inaccurated (less than actual usage)

besides, YMTiny has other features:

1. Sends typing notifications (settable)
2. More sounds
3. Message archive
4. Conference
5. Skins

to download this application, folow this link

download