authorwillow on "Text Widget Not Accepting Facebook Like Box"

I want to add my Facebook Like Box to my blog (this has the number of people who "Like" my page and others can click on it and sign up). However, when I put the code into the Text widget, as soon as I hit Save, the code disappears. Here's the code I enter:

<iframe src="http://www.facebook.com/plugins/likebox.php?href=http%3A%2F%2Fwww.facebook.com%2Fpages%2Fedit%2F%3Fid%3D140979655926616%26sk%3Dbasic%23%21%2Fpages%2FMiddle-School-Book-Reviews%2F140979655926616&width=200&connections=20&stream=false&header=true&height=287" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:200px; height:287px;" allowTransparency="true"></iframe>

Thanks, Willow