Are there any recommendations on the web browser based (not direct access because can't get around it through firewall) brokers to trade ES and other futures?
Look at lindwaldock.com or you can use IB Mobile trader via your cell phone or PDA (I trade using Sony Ericsson t68i with T-Mobile).
It is hard to tell whether it is the platform or the GPRS wireless technology, but it disconnects you once in a while, especially if you dont browse for more than 5 minutes. So I just refresh regularly every couple of minutes. Other than that it is enough for me to place limit orders and keep watch on the futures contract quotes all day long.
You could solve this problem w/o using broker with web interface. Take a look at this thread and relevant links: http://elitetrader.com/vb/showthread.php?s=&threadid=12231 I have not got that far, since I did not have time to tinker with soft. I am using gotomypc.com to access my home machine which runs IB. 19$/month.