So, this is how mounting the storage from my Droid phone worked for me.
Verizon Droid 2.0
Windows XP SP3
This is a fresh Droid system. No software installed yet.
1. Plugged in the USB
2. Noticed in the Ongoing menu (drag down the top bar) the "USB Connected, select to copy files to/from your computer."
3. Clicked on it.
4. Clicked on Mount.
5. In the file explorer My Computer, a Removable disk now showed the folders DCIM and LOST.DIR.
DCIM/Camera showed pictures I have taken and I can view them so that seems successful to me.
Now, I don't know where to put audio files yet, but that is the first step.
A couple of caveats.
1. The proper procedure in Windows after mounting a mobile USB storage device is to click on the "Safely Remove Hardware" in the start bar and click on "Safely remove Mass Storage Device F:". Then on the Droid click turn off USB storage. Otherwise you risk Windows corrupting your SD card which would mean you would have to reformat it.
2. After you have "Safely removed the hardware", you may need to reboot in order to remount the drive. XP has a bad habit of not letting you remount any USB storage device after safely removing it. Just the nature of XP.