Taken from:
http://www.codeave.com/html/code.asp?u_log=5080
<html>
<head>
<meta http-equiv="Pragma" content="no-cache">
<!-- Pragma content set to no-cache tells the browser not to cache the page
This may or may not work in IE -->
<meta http-equiv="expires" content="0">
<!-- Setting the page to expire at 0 means the page is immediately expired
Any vales less then one will set the page to expire some time in past and
not be cached. This may not work with Navigator -->
<title>CodeAve.com(No Cache)</title>
</head>
<body bgcolor="#FFFFFF">
<!-- There are two basic ways to prevent a page from
going into cache. Either one should work in the majority
of browsers. As with most meta tags they should be placed within
the head tags of your document -->
</body>
</html>
That is two methods of preventing the use of cache...
For refreshing--you can use simple Javascript and put a timer to "auto-refresh" every so often, such as:
<script language="javascript" type="text/javascript">
// the time is in milliseconds, so if you want it every day, it'd be: 1000 ms * 60 s * 60 m * 24 h = 86400000 d (one day)
setTimeout('document.location=document.location', 10000);
</script>
Note: you don't want to do this if 1. you have a lot of images AND you have dial-up users browsing (unless its only once every X days, or so) or 2. you are worried about your bandwidth.
If you wanted, you could use frames...and set only a specific frame to not cache, and auto-refresh.
There's also a million other ways...if I didn't say how to do something you wanted...or you want another way, let me know