There are services that take images and add music free, but there may
be a limit to the number of images for the "free" service. Once done,
you can download and burn for DVD's:
Additionally, if you have a Mac, just go to iMovie and create by
grabbing your images and setting to music you download to your
computer (as easy as popping in a CD or going to iTunes). Once again,
burn to DVD.
Although I'm a Mac person, I've also used Moviemaker since my district
is "PC", and it is fairly straight forward, though not as easy as
iMovie. Plus, Moviemaker is a free app:
In either case, you can do various dissolve effects to make your
slideshow more movie-like.
You might want to consider uploading your movie to "teachertube" and
let your students view it from there (100 MB) file limit for students
who can't buy a DVD ("youtube" has no size limit, but I've found some
unappealing pop-up ads alongside the videos).
Life is short, art is long...-Hippocrates