The AVG article is interesting:

What is DNSChanger?

DNSChanger is a Virus that is spreading. It is currently ranked 145 in the world for online threats. DNSChanger has been detected by AVG on victims' machines in 2 countries during the last month. There are currently 1 websites in 1 country that host DNSChanger.

Looks like it just the FBI that host DNSChanger, and it's active in the US and one other country. I also see that it affects all versions of Windows OS - so I don't think I'll bother any more about it.

Phil