I found this via the link below and thought I would share. The lines below can be copy/pasted into your .htaccess file for some added performance. What the real boost looks like is a little bit hard to grapple (for me at least), but apparently YSlow has taken me from an F to a high C, so I'm happy :)
Header unset ETag
FileETag None
<FilesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css|swf)$">
Header set Expires "Thu, 15 Apr 2010 20:00:00 GMT"
</FilesMatch>
via link: http://www.askapache.com/htaccess/apache-speed-etags.html