Detecting slapper
I have just found that chkrootkit now appears to detect the slapper worm. I am not sure, as of yet which variant, or if all variants are covered...but it is atleast something that server administrators should run to check....I usually run chkrootkit in cron to make sure everything is running as expected.
http://freshmeat.net/projects/chkrootkit/?topic_id=43