GSM/GPRS Shield WebClient Not Working, APN, USERNAME, PASSWORD

Help Please!!! I have a SIM900 GSM/GPRS Shield for arduino. I have tested the SMS Service and it has worked. I am trying to connect it to the internet via the SIM GPRS using the android example for WebClient and it is not working. I have tested it using the t-mobile and att sim cards with data plans. Still no luck. I have tested almost every apn, username and password that I could find around the internet. still no luck. Has anybody had any success. Please Help.