Google have launched an initiative to address the issue apparently... which, given their coverage, should help some I'd hope:

http://nakedsecurity.sophos.com/2012/05/23/google-malware/

I understand that the major anti-virus vendors have already taken steps to address the issue through their products.

The moral is, I guess, make sure you're running a reputable anti-virus product on your system... and that you're subscribed to your AV and operating system security updates?

I'm not sure exactly why it's not possible for the authorities to seize the IP addresses from RIPE etc. and re-route them to legitimate DNS services, in advance of the seized malignant DNS servers being taken offline... but it sounds like it isn't... or maybe that's what they did do and they just can't sustain running the workaround?

EDIT: Yeah... no, they just kept the botnet command and control system running for a few months...

http://www.theregister.co.uk/2012/07/05/dnschanger_botnet_shutdown/