Bluetooth is the key here.
If your cellphone has bluetooth then you can use one of the roving networks bluetooth adapters
Info here.Then you can use a simple serial terminal program on your cellphone.
I did this with both a windows mobile PDA, and Android platforms. Heck, i even did this with a
gameboy advance SP (with a flash cartridge).
Though i wasn't able to customize the GBA software as the author used some crazy outdated compile. The bluetooth was wired to the game link port on the back, which is literally a 3.3v TTL serial port. Even supplied power to the bluetooth adapter, i only needed to juri-rig up an old cable to make an adapter.
Bluetooth in it's most simple form, is a wireless serial port, which is why it's so readily suitable for robotics.
Any bluetooth equipped computer(laptop), cellphone, Tablet!, can detect the roving network devices as a software serial port.
For PC i suggest using the BlueSoleil bluetooth stack, it's just far more stable with bluetooth serial ports. Windows/widcomm/toshiba stack will cause send/receive lag.
You can't program a Basic Atom MCU over bluetooth due to timing issues, keep in mind. But controlling a device, sure no problem. All my stuff is bluetooth.