This is a pretty interesting approach...

'We have also postted a Fizzer cleaner to the actual URL that the bot downloads its updates from, as a self extracting and running executable.' The Fizzer-uninstaller posted there creates the file '%WinDir%\uninstall.pky', which then causes Fizzer to remove all of its registry keys. Looks like the Fizzer worm will soon come to an end."
Whole post on slashdot: http://slashdot.org/articles/03/05/1...tid=95&tid=172