To the OP, I don't want to sound too smarmy...or a little pretentious but...
Instead of going through all this trouble, looking for so many answers and coming out empty handed, cannot you just simply, save all your MP3's on a USB flash drive from your home PC and bring them to work and dump them on your work PC??
I assume everyone and their mother has at least a Gig or 2 or 4 Gigs USB flash drives these days, if you have a large Music collection, can't you just make a few trips everyday and dump most of your music from home to your work PC? ( or do it all at once with an external drive)
should be fairly efficient and easy process, just a suggestion, since as an owner of a huge music collection and and iPhone, I did the exact same thing, by dumping all my favorite tunes on my 16 gig Flash drive.
Just sayin...
( I understand if you update your iTunes/iPhone music on daily/weekly basis and you want to be sure you have the latest favorite music with you when you get in to work every morning. You don't want to be bothered with transferring the latest music to your work PC all the time...if that is the case, I can see it being somewhat inconvenient...)