Forcing a browser to NOT CACHE a file - so your updates show up for returning visitors

http://www.stefanhayden.com/blog/2006/04/03/css-caching-hack/

but you have to update every pages source code... ? just as easy as renaming file. might be other options in comments.

caching the proper way - http headers... 

http://www.mnot.net/cache_docs/

apparently things included by server side includes arent ever cached? could be wrong. 

again suggesting http headers - and using no robots for google old pages 

http://www.webmasterworld.com/forum21/10628.htm