I just had an almost 1 hour online chat with AT&T, but they couldn't solve my problem.

There are a few sites that I can't open with Safari on my iPhone.  I can with Wi-Fi, but not with 3G.  I went to Apple store yesterday and was told that AT&T is blocking these sites, but today AT&T tells me to call Apple 800 number.  This is exactly the problem I have and I tried 3 things that are mentioned here. 

http://reviews.cnet.com/8301-19512_7-10115258-233.html?tag=mncol;txt#comments

Turning on and off airplane mode seemed to work once.  I had an access to the sites for a few days and it went back to not accessable again.

Are there anyones who has a same issue, or any advices?