SlideShowPro is a great software for producing slideshows for your website. The latest version of Adobe Lightroom 1.3 has now the ability to use plugins and a plugin for SlideShowPro was recently released.
I think it’s worth mentioning, even if I don’t use SlideShowPro so far, I know that a lot of professional photographers do so. Maybe I will give it a try somewhen. At the moment I use Showit Web, developed by famous wedding photographer David Jay. Highly recommended!