How do I remove the Powered by Blogger from my Blogger blog?
In order to remove you will need to edit the blogger template and delete the attribution widget.

Please see this updated post for new Blogger Interface, Remove Powered by Blogger from new interface

Please backup your blogger template before you make any changes to it. This helps to revert back to the original template when something goes wrong while editing your template. The steps for backup and restore are discussed here in detail.

Steps to remove the Powered by Blogger text from your blog:


1. Go to Blogger Dashboard. Click on  Design. Click on the Page Elements tab for your Blog.
2. Click on Edit HTML and select the Expand Widget Templates checkbox.


3. Search for Attribution widget.
4. Click on Save Template Button.

5. A warning is displayed.Click on Delete Widgets and click on Save Template Button.




Source: sundeepmachado