Show off your IPv6 connectivity! This is a 1x1 widget that displays whether you are on an IPv6 or IPv4 network. The icon automatically updates as the device moves between networks. To use, simply add widget to home screen.

0 = No Network
4 = IPv4 Network
6 = IPv6 Network

Also gives information on the type of IPv6 address e.g. Teredo/6to4/Global

Needs Internet access because Android IPv6 APIs are buggy - http://code.google.com/p/android/issues/detail?id=13784 - fixed in Honeycomb.