I was given a similar task a week or so ago and after playing around with
a lot of image software that I hadn't used before found that Irfanview was
perfect.
It will create a single executable of a slideshow and happily play MP3s in
the background while it's running - the only thing you'll need to do is
look at the length of each piece of music and calculate the slide changes
appropriately
e.g I had a 6 minute track and 90 photos, so for the track to finish
completely in each loop I had to do a slide transition time of (60*6)/90=4
seconds.
Use the "Slideshow" option, set "Loop Slideshow" "Hide mouse cursor" and
"Loop MP3 files". Unset "Show text". Calculate the slide advancement
time as above and enter it into the "Automatic after x seconds" box. If
you have more than 1 MP3, add the MP3 file before each set of photos
adding up to the correct length - e.g 2 x 6 minute tracks, 180 photos, add
file 1 before the first picture and the second file before the 90th. I
only actually had one track, so you may find that you need to untick "Loop
MP3 files" if it doesn't turn out quite right...
Save as an EXE file and you're good to go - the slideshow can be run on
any PC, with or without Irfanview.
http://www.irfanview.com
Hope this helps,
Ben