This guy Core of wickedpsyched.net coded a version of AFP, the Apple Filesharing Protocol, for the iPhone and iPod Touch. This means that you could enable filesharing on your iPhone and copy some files over directly from your desktop over wi-fi. If you ask me, this is better than disk mode, where you can plug in your iPhone and it shows up as a removable disk. It apparently doesn't show up in Installer.app yet, but give it a few days and I'm sure it will be there.
There's also great news if you're more of a windows person. Say you just prefer the Samba/SMB/Windows Filesharing so you can share with windows and mac, well he's got you covered there too.