This question was asked recently on the Moodle.org forums (http://moodle.org/mod/forum/discuss.php?d=148753#p650609). The user wanted to embed a Slideshare.net presentation onto the Moodle home page only for users that who were not yet logged in to see. The question was fielded well by Mary Cooch (@MoodleFairy).
To enable the ability to add both activities and resources to your home page, access your Administration block (you must be a site administrator to make this change). In the administration block you’ll find “Front Page” and “Front Page Settings”. Use the check box to “Include a topic section”.
After saving your changes, when editing is turned on you’ll see both a topic summary and activity/resource drop downs to add content to your home page. To add your embeddable content just add a label or edit the topic summary and embed the code. This is what your Moodle site might look like with a presentation or video embedded.
Now, if you want only a select group of users to see this, e.g. guests only, editing locally assigned roles of a label or activity will provide you the option to “show” hidden resources to users that are logged in as guests (making a unique way to show content to visitors but not necessarily those who are well versed with your site.
For more information about this easy Moodle work-around visit the forums: http://moodle.org/mod/forum/discuss.php?d=148753#p650609