Facebook has changed the rules… Again!!!
I just created a small video to help you on showing flash content with iframes, because now it’s no longer possible to add new FBML tags. Click on the image below to play the video.
 

*Video:facebook iframe - how to add flash content

Here are the steps that you should follow:
1 – Login to your facebook account

2 – Go to the developers section (click on the lower menu button)

3 – Select “My apps” on the upper menu

4 – Click on Set New App

5 – Give it a name, accept the terms and enter the Security Check code

6 – There are a lot of options, but you need to enter at least the followig:
a) Canvas URL – The directory on your server where the flash object is located
b) Tab URL – The page on your server where the flash object is located

7 – Save changes and click on “Application Profile Page”. It’s time to link this application to your Fan Page

8 – Click on Add to My Page and select the Fan Page you want this new App to be displayed

9 – You’re done. Visit your Facebook Fan Page and you should see a brand new button on your left menu