Help me to win the battle with browser's cache

Hello php-general, I have index.php, which has <a href="index.php?logout">Log out</a>. When I click it, I am logged out the site. But I type "index.php" in browser's address bar, press Enter and ... it shows "non-logouted" page. What should I write in php code to tell browser something like "forget about old page, don't display it, get the newest version"? Some time ago I tried to do that in several ways and nothing gived 100% result. And other thing I saw was that Netscape and Explorer behave in different ways in such cases. Could someone help me? Maybe this topic was discussed before, but still... I appreciate greatly any suggestion. -- Olexandr Vynnychenko mailto:supaboy@i.com.ua