Hi Alex
I'm not very used with those meta-tags myself, because I'm working in a "controlled" environment on Intranet only. I haven't done severe testing though but I'm quite sure this meta-tag is scoped to the page it's in. Thatfor you should place it in the header of every page you don't want to be cached by a proxy. In a frameset this would mean in the content pages where your changing data is in. So you can make that part of the frameset that's static cacheable and force the browser to reload the content pages from the source.
Btw I just discovered another tag that might be helpful
< meta http-equiv="pragma" content="no-cache" >
This also orders proxy agents not to cache a page. I don't know if they both are really working the same way. So just use both of them in a row ;)
Regards
Markus