Another list of IPv6 Internet Exchanges can be found here: IPv6 status of IXPs in Europe
TIX (tallinn interneti exchange with ipv6 support)
Euro6IX, European IPv6 Internet Exchange Backbone
French National Internet Exchange IPv6 (since 1.11.2002 active). FNIX6 provides a free and reliable high speed FastEthernet interconnection between ISP located in TeleCity Paris.
INXS: (Cable & Wireless) Munich and Hamburg
AMS-IX: Amsterdam Internet Exchange
NTT, United Kingdom - IPv6 Trial. IPv4 Tunnel and native IPv6 leased Line connections. POPs are located in London, UK Dusseldorf, Germany New Jersey, USA (East Coast) Cupertino, USA (West Coast) Tokyo, Japan
ESnet, USA - Energy Sciences Network: Tunnel Registry & Address Delegation for directly connected ESnet sites and ESnet collaborators.
Hurricane Electric, US backbone; Hurrican Electric Tunnelbroker (also available under http://tunnelbroker.com/) Press Release: Hurricane Electric Upgrades IPv6 Tunnel Broker Tunnel Broker Endpoint Autoupdate, Perl Script
Public 6to4 relay routers (MS IIE boycott!)
Note: These services are mostly only available with a valid IPv6 connection!
Quake2 over IPv6
Something missing? Suggestions are welcome!