1. Go to slideshare.net and create an account if you don't have one.
2. When you have your account, log in and click on your name. This will display all your powerpoints.
3. Click on the grey box that says 'upload'.
4. Select the file to upload and click.
5. Now you have to make some decisions about if you're going to make it public or private.
6. You'll have to wait a few minutes as it converts the file. Be patient. Once you've done all that, then watch this screencast about finding the embed code and posting it to the wiki.