You can send and receive Twitter tweets through Maxis.
According to the FAQ, you can send and receive unlimited SMS tweets for just RM1/week.
Activated by sending "ON TW" to 28933 (2twee). Unsubscribe by sending "STOP TW" to 28933.
I am just wandering what take them so long to came out with the service in Malaysia. The service is provided by Maxis and nPlay.