I want to use a Nokia phone, e.g. 6310i, 6230, 6610i or 6630 for connectivity purposes for a proporietary PC-based application. The phone is connected using DKU-2/5.

Is there an embedded TCP/IP on the phone and how do I access it. More importantly is there any suitable SDK to support such things? Or do I need to buy a special GPRS module with built in TCP/IP?