Okay chalk this up as another website I had no clue existed. I mentioned the Bank of America mobile website a bit back. That got quite a large response so I thought I would mention the American Express mobile website that I just discovered on Wapreview.net.
You just head on over to www.amexmobile.com from your Berry to check you card balance, most recent transactions/payments and even pay your bill.
Pretty cool I know I will be using it.