On this page, IPv6 security related information is presented. Latest after you managed to get IPv6 up and running you should thoroughly give security a serious thought and configure your firewall correctly. You should have reasonable theoretical background to it and it's recommended to do some practical assessments with tools.
For the theoretical background there are some online publications as well as some books. For testing the wanted and not wanted accessibility of your IPv6 network and your IPv6 router there are below some link to tools.