Xbox360 will gets a USB memory storage support via system update over Xbox LIVE on April 6th. This will allow you USB flash drives to be used for storing game saves, demos, movies, profiles and more.
After update, you could use USB flash drives up to 16GB , “USB Hard drives may work, but like flash memory, you’ll only be able to use up to 16GB of space. Since performance on flash based USB storage is usually better, I highly recommend using flash based instead of spinning media like a hard drive…it’s just going to give you a MUCH better experience.”
A couple of points:
- You can have 2 devices connected to the console at a time, enabling up to 32GB of simultaneous storage.
- The system won’t just configure the device once it is connected to the console. You’ll need to head to the memory area in system settings, select your USB Device, and choose from Configure Now (Format and Configure the Full Device), or Customize (you can choose how much memory you want configured for Xbox360 from the free space on the device.)
Source: Major Nelson