wireless usb disk?

"There is no USB sized device I am aware of that does this right now, however I can think of a way you can do this. Firstly I do not know your exact scenario which you would like to use this under, so I will make a few assumptions so I can give you something that will work.

Running a USB key like this would be a problem because USB keys require a 5 volt power source to function properly. a USB flashdrive proper is not up to this challenge however moving up to a stand alone usb drive that also has a network port and tcp/ip capability is just what the doctor ordered here. It may not fit in your pocket, but it will work just fine working from a fixed location like where your wireless router is situated.

Lacie makes a 1TB drive that has a built in ethernet port.

You could miniaturize this type of solution with a gumstick computer running linux ,an IP stack, wireless adapter and a USB interface you can plug a thumbdrive into. You would need to carry a battery with you if you wanted it to work from inside your pocket however."

Well, there is Eye-Fi SDHC memory cards, but they are powered by the camera. If you have a camera that supports SDHC cards and can fit in your pocket, then you're golden.