Not with the default firmware. Go for the Kfurge custom firmware and then ushare (which works with xbox360, but is clunky) or fuppes (nearly working - i've written a howto in the tutorial section; i WILL have it working properly soon!)
If you nervous about the custom firmware, don't be - most of this forum have done it, and its not too scary: I have limited linux experience, but i managed it and was WELL worth it....i'm on a mission to get the best media serving option for the 360!