I have tried Sixxs.net to activate ipv6 - but it seems not to work.
Then I tried to add IPv6 through tunnelbroker.net, and this installed 
with a lot less hassle than Sixxs does.

Sixxs, took me 2 days before everything was in order (because they check 
manually)... tunnelbroker, took me just 10 minutes !
I can now access ipv6 sites fine.

Now the real question : if I open for instance port 80, to my Vista 
machine running IIS... all goes well, ... locally ?! But how can I check 
that this is remotely working, without having to set up a second site 
using ipv6 ?
I can access the domain I created, with the AAAA record created, but 
this is definitely just through localhost - can't image that this is 
working straight out of the box :-) (I tried to modify the port into 
monowall, and still it is possible to access my IIS... so I know I'm 
going over the localhost instead)

Kind regards,
Michel