Flixtime is a site I just learned about from the award winning blog, Free Technology 4 Teachers. This is a site similar to Animoto that it lets you create amazing slide shows.
There is a lot to like about Flixtime such as: their cool graphics, excellent song selection, and the ability to control transitions in your show.
I highly recommend giving Flixtime a try by clicking here.
Below is my example (ignore the watermark)...