NOTE: These instructions are somewhat general because YouTube regularly makes changes to the layout of its website. From these instructions, however, you should be able to navigate through and get your slideshow movie uploaded.
- Go to YouTube.com and either log in to your account or create a new one.
- Click the Upload button
- At the file selection dialog box, navigate to the iPhoto Slideshows folder inside your Pictures folder [iPhoto '09] or your Movies folder [iPhoto '08] and select the file that has the same name as your iPhoto slideshow.
- For the Privacy option, you can choose whether your slideshow movie is Public (viewable by the world) or Private (viewable by up to 25 people that you define).
To get the URL of your new YouTube video, click on the Play button and copy the URL out of the Address field (Command-C) at the top of the window in Safari. Once you have the URL you can send it to the people you want to share your slideshow with.