This is one of several issue that has kept me (so far) from making the leap and buying an iPhone. I have a Treo 650 (pretty old phone!) and use it to bluetooth ringtones, files, programs, pictures, and contact information between myself and other computers and other bluetooth-enabled phones. If I couldn't bluetooth items for some reason, I could always count on beaming the information through infrared. I also sync through bluetooth which is wonderful!
I also use bluetooth to connect to the internet through my PC to download large files (like audiobooks) because it's faster than using the phone's GPRS connectivity. Of course, that functionaly would be unnecessary with the iPhone's wi-fi capability, which I don't have on my Treo.
I'm sure that the iPhone will win out in the end (it's just so darn cool!), but I have a list of functionality items that I know that I will have to give up when I do (waiting for 3G like so many others). Bluetooth file transfer is one of them.
Lisa