Currently I'm looking at attempting a web request and seeing if that fails to determine if I'm online or not, but ideally it'd be nice if there was some hook in the OS that would alert me when I'm offline and go online.
Does anyone know if this is possible today?
It looks like the com.palm.connectionmanager has what you need:
http://webos101.com/Connection_Manager
http://webos101.com/Code_Snippets
Enjoy!