There's a new iTunes feature that lets you control someone else's iTunes library from your iPhone, while at a party or a hip, downtown blogging headquarters in Nolita. Is this a good idea? Only maybe.
iTunes DJ works like a jukebox, sort of. You can't change the song currently playing, you can just vote on songs currently in the queue, moving them up or down in the list, and you can add new songs from the library. So if the host's collection is pretty SWV heavy, but you'd prefer to mix in a little R. Kelly, you can do that! Or if your coworker is really into early Black Sabbath but you want to tap into their little-known Jill Sobule menagerie, hey, go for it. Now, the drunker or more spiteful people are, the pushing up and down, up and down, of the various songs on the queue may get a bit too heated and frequent, but barring people being jerks (which most people are), it ought to work pretty well.
For those of us who have secret, terrible songs in our iTunes library that no one should ever know about (I only have those High School Musical songs so I can lure teenagers into my car, not because I actually like them, I mean jeez Louise...), the idea that someone with a magic internet phone could just go riffling through any dark corner of our music collection is horrible. So, even though you get to decide whether or not you want to allow people in, it's still a drawback. What if you forget about a particular song, and then all of a sudden people burst out laughing and then the first lilting strains of "Coat of Many Colors" come trembling over the speakers and you want to die? Yikes. But in terms of creating as democratic a musical environment possible, it's a sound (heh) idea.
So, yeah, get on your phone tube and order up iTunes DJ. Then crank the Skynyrd and hope to God no one finds that small pocket of B*witched tunes. Though, if they sort by "Most Played," you're fucked.