Dedicate the 8th of June to IPv6. The Internet-Society together with major organizations like Google, Facebook, Yahoo and others will be testing IPv6 for 24 hours. The ultimate goal is to get the attention of all stakeholders and motivate them to prepare their infrastructures for a smooth transition to IPv6 from IPv4. If you already started your IPv6 test implementation I suggest that you participate and join the test flight by visiting this page.
If you are participating in the IPv6 Day, then testing IPv6 access to websites requires some configuration such as, setting quad-A records in DNS but I suggest that you plan ahead and inform your users or customers that might be affected by this transition. Make sure that your help desk is equipped with the necessary information and have a fall-back plan in place. It is important to coordinate your plan with your upstream ISP and tackle any issues beforehand. One final suggestion is to avoid performing works or changes to your network setup during this day. For IPv6 and Windows go here.