In India Apple iPhone is neither a common-device nor is it officially available for any other service provider than Airtel and Vodafone, and hence customer-care representatives of non-iPhone carriers fail to provide a working GPRS settings for these devices. The same problem was faced by me while configuring IDEA GPRS on my friends Apple iPhone 4, luckily configuration was as simple as entering IDEA specific "APN" value just like we did in BSNL GPRS Configuration earlier.