This form will take you to Blogger where you can choose to install the search widget into your sidebar (or other element of your template). However, if you prefer to install the search widget manually, you should take the following steps:

   1. Go to Template>Layout in your Blogger Dashboard.
   2. Create a new HTML/Javascript element in your sidebar.
   3. Insert the following code into the widget:

          <p align="center"><form id="searchthis" action="/search" style="display:inline;" method="get"> <input id="search-box" name="q" size="25" type="text"/> <input id="search-btn" value="Search" type="submit"/> </form></p>

   4. Give your widget a title if you like (eg: "Search this Blog"), and click save. You should now have a fully functional search box in your blog's sidebar!

So, if you prefer something simpler than the Google blog search I wrote about before, this is surely the widget for you.