Sometimes there's a proxy server between you and the actual web server. In that case META http-equiv tags won't do the trick; the server must send out http responses with real headers (which the proxy will see) that disable caching. Also there are several mechamisms for cache control and not everything takes notice of all of them so you need a belt-and braces approach -
cache-control : no-cache
expiry time (sometime in the past)
pragma: no-cache

To get these headers out you need to do server side scripting. In PHP it's the header() function, for example.

Anahata