<p>Does anyone know how to get/set the call divert settings in codes running on Windows mobile 5/6? I am new to windows mobile development and wonder if there is anyway to do it using C# and .NET CF?</p>

I assume you mean call forwarding?  In general terms, the
Telephony API (TAPI)
is used for programmatically controlling the phone interface.  Call forwarding is specifically handled by
TSPI_lineForward
.
Microsoft does not offer any built-in or SDK tools for managed developers to use TAPI, and the structures TAPI uses are cumbersome and difficult to P/Invoke.  There are a some
3rd-party libraries
that do provide some level of TAPI interaction that you might also investigate.