Photobucket

A Free Basic Membership Flash Slideshow
Photobucket.com

Slide

Slide.com

Slide will work in any site that allows Flash Objects. Their image storage is free and they also offer a custom skin generator. They make every option imaginable available except for the deletion of the link buttons on the finished product.

Flickr

flickr.com a YAHOO! company.

Flickr is an "online photo management and sharing application" For more information, there is an online tour.
Their basic accounts are free however you must have a yahoo email address to join.

Picasa

Size Medium Slideshow from Picasa Web Albums

Picasa also offers free software for organizing, editing and printing your photos.

Google - Blogger - Picasa

Download Picasa 3 (beta)

It's all free to use
Picasa is free to download, and Picasa Web Albums provides 1 gigabyte of free storage -- that's enough space for 4,000 wallpaper-size photos.

Using Picasa Web Albums you can create a Flash slideshow to embed in your blog or webpage. Each slideshow features built-in playback controls, size options, and the ability to display captions.... more on how to embed slideshow