What you're asking for, I believe, is a web browser implemented from the emepg's front panel. Currently no one has implented anything like this. The only way to get GIFs or HTML pages up on the empeg's screen is to convert it from another file format (in advance) and use it as a replacement for the Image Pan graphic. Not an ideal implementation.
As far as getting the signal from the cell phone, if the cell phone's got a standard serial port or an ethernet port, no problem, and your only barrier is writing the appropriate software. Otherwise, there isn't much you can do.