The current PocketPC module does not support SmartPhone, but I think you can write your own library/C code to access the SmartPhone APIs, and wrap it with the Call Library Node to use it from LabVIEW PDA.
You have to install the PocketPC Smartphone SDK in order to use the APIs.
The same goes with the PalmOS module. It currently does not support PalmOS Telephony services but you can write your own code to access the Palm OS Telephony API and wrap it with a Call Library Node.
More info: http://www.palmos.com/dev/support/docs/palmos/TelephonyBasic.html