[stoneage]

Is there a good app to combine two .mp3 files to make one soundtrack for an iPhoto slideshow? I don't think you can use more than one file for a slideshow created in iPhoto. I don't want the song to repeat and I want the slides to appear for more than 1 second.

[analogika]

If you want control, use Garageband. You can drag iTunes songs right into the arrangement window and cut, re-arrange, fade, etc. to your heart's content.

Alternatively, if you just want simple joining of files:

http://www.hornfred.de/rejoiner/index.html