Schema for EMails and Contacts

Hello,

I am working on a diploma thesis about an old idea of mine,
Integrating all data that I access every day into a central system using 
rdf (ought to be useful somehow).

One goal is to include all Emails, Contacts and Appointments of mine 
into a RDF model/database.
I have followed the project that is about PALM integration (as i am 
using a palm myself).

Now I am searching for a schema that describes *emails, contacts and 
appointments*. I followed your VCalendar / iCal discussions and I got 
the impression that its not very easy to implement applications that 
make use of rdf in this topic.

But I think that RDF is the "killer" in personal knowledge management 
and therefore I want to create a wrapper for MS-Outlook that transforms 
MS-Outlook into a RDF Model on the fly - but

- Which schema describes Emails, contacts and appointments 
(Microsoft-independent) ?
- Where can i download it .... ?

I already found some schemas in the Netscape/Mozilla RDF thingy, but my 
feeling says that there has to be some CENTRAL schema for this stuff 
that experts like you all know about...

Greetings from Vienna/Austria
Leo Sauermann
TechnicalUniversityVienna