device that connects the arduino fio micro-controller to a smart phone

Is there any device, through bluetooth or wifi, that could connect the arduino fio to a smartphone? I am trying to make an app that would send inputs to the fio and then through the fio to the rfid reader...

You want to send data to an RFID reader? Personally, I think you need to rethink this project.

Like trying to write to an analog pin.

I meant communicating between the phone and the arduino. Sorry for the confusion

One option is to get a Bluetooth chip. Most are USB (unusable without additional hardware) or UART (problems sharing communications with Arduino USB), but I suppose SPI ones exist.

In one project where I needed to interface an Android tablet to an I2C bus, I used a homemade "Kelly Wu" board, which uses a PIC24FJ64GB002 to provide USB host.