This was in today's tech update, but is actually dated from the 20th. If you are using the 'new' Adobe 9, and have not heard about this, it provides useful info and suggestions to a take preventative actions about this ongoing exploitation.
http://blogs.zdnet.com/security/?p=2631&tag=nl.e539
Or, for the sake of sanity:
Click: Edit -> Preferences -> JavaScript and uncheck Enable Acrobat JavaScript.