I thought I would post some links to a couple of slideshow apps I have been trying out. The above was made with Animoto. You can link it to your flickr account and choose from a selection of musical options. It then edits together a short music video for you (30 second pieces are free, anything more and there is a fee).
I have also been trying out slideoo (which I used for the post above), FotoViewr, and splashr.
Slideoo is a horizontal scrolling slideshow that reminded me a lot of the Vuvox collage app. You can move through it by clicking on either end, or by dragging a scroll bar on the bottom. Clicking on a photo will take you to its flickr photo page.
Fotoviewr has four different viewing styles, all of which look very good, and remind me of Cover Flow in iTunes. There is also a full screen option, but currently there is not an embed option for your blog or web page (supposedly coming soon).
splashr has 23 different viewing styles with the ability to embed. However, when embedding, the default width is 1000 px, which is too large for most blogs, and changing that size lowered the quality of the images in the slideshows.