Is there anyone who have this answer. There is this Facebook Page by Pizza Hut UK. They have this feature... when you are not still a Fan of this page... it will show you a banner (Note: The tab is the same 'Offers'). But when you like it... the banner disappears and a list of offers are been displayed without the 'Offers' tab getting changed. I hope my explanation is clear to understand. Does anyone know how we can do this?
You need to add FBML to your page, it's an application. Afterwards, you can define a tab that will be seen by visitors. FBML (kind of a Facebook code language) allows you to make such pages and even more.
I believe this is called Fan gating, there are various apps you can use to do this if you are not into iframes - try Pagemodo or TabSite Louisa
All of it are done by FBML then you able to set it to show before or after you join the fan pages. Even twitter also able to do it.
TabPress is a FB application you can use to do this. I use it for my fan pages and it's really helpful.