Okay, I was hunting around the net for a workaround to the
problem I blogged about yesterday, and I did in fact find one. A clever guy by the name of Andrew Grant posted a means by which you can trick your version of iTunes into thinking its the same instance running on another computer. The net-net of this is that you can manually sync your iPhone easily with either computer adding music to it from either location.
Here are the instructions. I verified that this method does in fact work and I have been happily adding and deleting music to my iPhone from both work and home.
Note: You do this at your own risk. If you make a mistake, it is altogether possible you could render your iTunes (or even your computer) inoperable.
Update: Be very careful with this method. I had one of my iPods set to automatically sync a playlist on one computer (not the other) and when I plugged it into that other computer (to charge it), iTunes came up, silently deleted all my files on the iPod and *then* complained that the playlist didnt exist. D'oh!