Umm, this is interesting..

[Arnoud Engelfriet]

Shane Martin Coughlan wrote:
> I believe setuid and Arnoud were both referring to existing code
> previously distributed when using the term 'revoke' above, and in that
> context the GPL cannot be revoked.  The author is free to stop
> distributing new copies of the code or change the terms under which new
> copies are distributed, but that's another issue.

The terms of new copies are governed by GPLv2 section 6:

"Each time you redistribute the Program (or any work based on the Program),
the recipient automatically receives a license from the original licensor to
copy, distribute or modify the Program subject to these terms and
conditions."

Can the author stop granting *these* licenses? If so, that'd stop
redistribution right there and then. That's the only effective way 
to "revoke" the GPL I can think of.

Arnoud

-- 
Arnoud Engelfriet, Dutch & European patent attorney - Speaking only for myself
Patents, copyright and IPR explained for techies: http://www.iusmentis.com/
              Arnoud blogt nu ook: http://blog.iusmentis.com/