Sarna.ORG is fully IPv6 enabled, and should be accessible from v6-only hosts. Most of the internal traffic on my home network is also IPv6. If you are accessing this page by IPv6, you will see a dancing daemon in the image below.
IPv4 addresses are currently expected to run out in 2012. While the slowed economy has pushed this back a bit, and increased use of NAT (and NAT of NAT of NAT...) will provide workarounds, NAT has many drawbacks and at some point the situation will become unworkable. Hurricane Electric provides the meter below projected exhaustion. For details of how the date is estimated, see the IPv4 Address Report by Geoff Huston.