Is the usb port speaking the standard usb storage language?
I dont really know the details. If you plug it in you can
talk to it over a debugging interface over the usb ("adb").
But you can also set it up so that the sdcard in the phone
appears to be a drive over the usb port.
The usb connector on the ADP1/htc dream/t-mobile g1
also has some extra pins that have a serial port thats
usually used for a kernel debugger. You can turn that off
and use it as another tty device. Some model phones by
other manufacturers dont have this serial port.
Mostly only my phone I talk to it using the "adb" link
and over tcp/ip to the wifi.
Tim Newsham
http://www.thenewsh.com/~newsham/