Remove the Blogger NavBar

To hide it paste the CSS definition between the style tags:

<style type="text/css">

#b-navbar {
height: 0px;
visibility: hidden;
display: none;
}

</style>

Hiding the banner in Blogger Beta (iframe):

<style type="text/css">

#navbar-iframe {
height: 0px;
visibility: hidden;
display: none;
}

</style>

Just remove the code to show it again.