Getting rid of blog spam

I discovered that my blog was infected with malware that inserted spam text into the version displayed to search engines.  So, the blog looked fine when accessed directly, but showed a bunch of sexual enhancement product ads when viewed through Google's cache.  So in case you were wondering: no, that was not intentional!  This is apparently a common form of attack, since it's not obvious at first that something is wrong. I believe the malware has now been removed and the blog updated to prevent a recurrence.  It may take a bit of time for the Google cache to update and reflect this.