Download iPhoto Export from .....
http://www.hagus.net/files/iPhotoExportBeta1.7.zip
Use this to export your images from iPhoto.
Change the name of the "index.html" file to something like "SlideShow.html"
Upload all the files to your server. They should be in the first level of your directory i.e. not in the folder you created on the desktop.
Create a link in iWeb to this page and check the "open link in new window" box.
The link will be something like......
http://www.yourwebsitename/slideshow.html or
http://web.mac.com/YourName/YourWebsiteName/SlideShow.html
Clicking the link on your website will open the slideshow in a new window so that you don't have to click the back button to return to the main site or code a back button into the slideshow page.
If you are using .Mac, drop the files into your website main folder using the path Finder/Go/iDisk/MyiDiskWeb/SItes.