Can I use my iPhone as a remote control for Comcast Xfinity?

Yes, you can. All you have to do is download the app from the App Store. There is an app for the X1 system and one for the non-X1 system. Once you have the one you need, simply log in with your Comcast ID and it will set up for you. You will be able to access all the functionality of the regular remote, plus issue voice commands in the X1 version.