Nope. Gotta do it from a USB. I prefer navigating the iPhone/iPod menu over the hard drive menu. iPods also give you cover art - not essential, but gotta put something on that huge screen
When I loaded some music to the hard drive, all I did was make a folder on a flash drive and drag in the playlists from iTunes. I did this on my Mac, but it should also work with a PC (or try copy/paste). It's pretty simple. Aside from not being a fan of the way you navigate the HD music collection, I also didn't like having to wait so long for the music to load. I don't have a garage to lock my car in while this occurs, so I had to sit in it while waiting... burning gas the entire time (killing the engine wasn't an option as it was 95 degrees outside). I suppose you could load it while on a long trip, but you can't do anything in iDrive while it downloads.
I prefer plugging in my old, deactivated iPhone loaded up with all of my music on different playlists. I get cover art, it's easy to navigate, and new music can be added easily without the hassle of the hard drive.