How do I use more than 1 song for Slideshow?

This is what I do:

In iTunes, make a playlist with the songs you want. Then from iPhoto select the playlist you just made.

After you select the playlist in iPhoto, make sure you don't click on one of the songs below it. If you do, iPhoto will only use that one song rather than the whole playlist.

Unfortunately many (including me) have reported that sometimes when a slideshow is exported only the first song from a playlist can be heard. The rest of the slideshow is silent. There is no apparent rhyme or reason for when it happens. Once this happens the only way to fix it is to re-edit the slideshow in iMovie or Quicktime Pro.

Here's my solution. It is a bit complicated, but you can make your song mix perfect for the slide show by cross fading the music and even editing it.

Open iMovie and choose "Audio" and look for your songs in iTunes. Drag them to the time line in the order you want them and edit them and cross fade, etc, whatever. Don't worry that there's no video to go with it. When the sound track is as you want it "share" it as an aiff file , it's in the expert settings under "share>compress movie for expert settings".

After sharing make sure you have a new file saved that is the soundtrack and close iMovie. Open iTunes and drag the track to the iTunes icon and add it to the library.
Next time you open iPhoto you'll find your soundtrack waiting for you in the iTunes library, choose it for your slide show song and you're done.