First of all you need to contact the Cell Phone manufactuer to determine 1) what requirements and limits are imposed by the architecture, 2) is there a SDK available, 3) does the software you are intending to build already exist, and finally, do you need a license to deploy? Most cell phone vendors as you can imagine would not take kindly to their phone being used as an open development platform. In fact, lets say you jump through the necessary hoops to get started, you almost certianly be required to have your sofware certified to run on the phone os. Deployung an aplication without permission is definitely a legal mistake. Ever take the time to read your cell phone contract? One final note, Java is the preferred development language because of specialized VMs that have been ported to the Motorola chipsets. While Java is not just like C#, the similarities are pretty close in terms of streams, sockets, and event handling. If you are still interested in 3G software, you might start investigating the new Smart Phones touted by Bill Gates. Since the objective is to have Windows CE as the platform you will have an opportunity to do some embedded development for whatever features phone vendors offer in conjunction with the tools Microsoft offers. Mike Luster CTI/IVR/Telephony SME