Robert,

> The one serialization format that jumps to mind is CORBA.  

As the resident CORBA advocate on E-Lang :-), I agree completely 
that the CORBA CDR (Common Data Representation) specification is 
a strong open and neutral starting point for data encoding and 
serialization in CapTP. 

> There are language serialization bindings for Java, 
> Smalltallk, C, and C++ (and probably others).  

...Ada, Python, Lisp, (informal) Ruby, Eiffel...

> Since CapTP is specific to the kind of system that E is 
> building, it may not map to the CORBA concepts of BOA, 
> IIOP or GIOP. 

Its probably better that it doesn't. Based on my understanding 
of the two architectures, I'm coming to believe that the CapTP
on VatTP is actually a much cleaner architecture than GIOP (of
which IIOP is a binding to TCP/IP as a transport). Artifacts
that are equivalent to the BOA and POA will probably be needed
for languages that don't directly support the eventual send and
capability concepts.

>    Be that as it may, the OMG serialization standard is 
> useful in its own right.

I personally think that the relatively recent extensions for 
ValueTypes (which allow CORBA to provide pass-by-value as well 
as the original pass-by-reference objects) are particularly 
important, since they also provide the semantic foundation for 
translation to XML for cases where a webservices- or human- 
readable format is needed.

-DMC