[liluqun],
At the moment, the CLDC/MIDP specification does not provide any native APIs that can allow a developer to access the native SMS platform specific function on the mobilephone or the Palm devices.
One workaround that I can think of is to implement an SMS gateway on the telco service provider site that can accept HTTP connections from the mobilephone or Palm OS wireless handheld device and send an sms on behalf of the devices.
HTH.
Allen Lai
Developer Technical Support
SUN Microsystems
http://www.sun.com/developers/support/