One of the reasons people resist changing over to IPV6 is a fear that their favourite sites and resources may become inaccessible. If you're curious about whether a given site is accessible via IPv6, a simple search using this CGI script developed by engineer Mark Prior will tell you if its server has an IPv6 option, and whether it supports the protocol for other options such as SMTP for mail.
As Internode founder Simon Hackett told us recently, sites gathering the coverage to switch on their IPv6 option is a process that will take some time. (And yes, before everyone points it out, Lifehacker hasn't made that move yet.)
The site also contains a roundup of prominent sites and their current IPv6 status, which shows that there's still a fair way to go.