There are two versions of the embed code on SlideShare. We recommend you use the new version that starts with <iFrame…>. You can access the new (iFrame) embed code by clicking on the Embed button on the top bar of the player. See the screenshot below:

However, the old version of the embed code is still available. If you want to use that, click the Customize link as shown in the screenshot. We suggest you use this only if the website where you are embedding does not support iFrame.  However please note that this old code will not allow embedded content to be viewed on Flash and iDevices.

This is the view after clicking on the Customize link:

If you are embedding in a Wordpress blog, you can use the new iFrame code for Wordpress.org blogs, or use the Wordpress short code if you have a Wordpress.com blog. To understand this better, read this FAQ.