ccw is called com callable wrapper where as rcw is called as 
runtime callable wrapper.

These are business objects(Components).

CCW is the Com Callable Wrapper. This will buily a bridge 
between the Com Component and the .Net Component
RCW is the Runtime Callable Wrapper. This will built a 
bridge between .Net Component and Com Component.converts 
the .Net data type to Com Data type

RCW :- we are using COM Component in .Net application 
directly we can't call. That's way we need to create a 
wrapper trough Tlbimp.exe read COM classes and interface in 
assembly metadata.

Com Callable Wrapper 
1)Create Assembly and compile with strong name. 
2)Register Assembly using regasm <assembly name> 
3)Register Assembly in GAC using gacutil /i <assembly name> 
4)Use tlbexp <assemblyname.dll>  to export Assembly as Type
Library for COM. 

Runtime Callable Wrapper 
1)Create Public Key Token file using sn.exe &#150;k
<keyfilename.snk> 
2)Use tlbimp <TypeLibFileName> /keyfile: <keyfilename.snk>
/out: <AssemblyName.dll> 
3)Register Imported Assembly in GAC using gacutil /i
<AssemblyName.dll>

Com Callable Wrapper(ccw) build a bridge 
between the Com Component and the .Net Component
Runtime Callable Wrapper(rcw) will built a 
bridge between .Net Component and Com Component.converts 
the .Net data type to Com Data type