Recently worked on a facebook application app. and faced a strange issue in submit a form. The form submission was working perfectly in all other browers like Firefox, Chrome etc. After googling, got the following life saver link.

http://stackoverflow.com/questions/3871199/facebook-iframe-not-working-in-ie-session-login-issue

For IE, need to add the following script

header('P3P:CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT"');

I hope it would be helpful for others.