By the way, in case you're hoping to use iTunes for a wedding reception, here's a helpful little trick I learned.

Basically, what you really want/need is a playlist of set songs that will play in order, but you can queue up a new song if you want to play next AND have songs disappear from the list after they've been played (so you don't get any repeats). There's no simple setting to do this, but there is a fairly easy trick using iTunes DJ, which sits right above you playlists in iTunes.

Now... when you use iTunes DJ, you set the "Source" from a dropdown box near the bottom of the screen. The problem is that it will randomly pull songs from that playlist, and, for some reason, isn't great about not replaying songs you recently heard.

But, try this. Maybe a blank playlist, a playlist that has no songs in it. Set iTunes DJ so that the Source is this blank playlist. Once you get an empty iTunes DJ, cut and pastes your entire, say, "wedding - dancing" playlist into iTunes DJ and now you have that entire playlist in DJ, in order.

Why is this better than simply the playlist? Because you can right click on any song and hit "Play Next in iTunes DJ" and it will jump to the next song in the queue. You can even add songs from other playlists.

Obviously, it's not foolproof, you can still do something "sucky sucky," but overall it's a handy tool (with a little preparation and practice).