Aaron Axelsen

The Advanced Search Widget is designed to be a replacement to the defaut search widget. The Advanced Search Widget allows you to search for only a 
specific post type and also select which fields to query (title, content, tags).
In addition, it is also possible to place multiple widgets onto the sidebar to search through different custom post types.

Advanced Search Widget

Allows you to add a widget to search custom post types along with other options

asimeon

Costumizable search widget. Shows the search results dynamic on your sidebar.
Features:
<ul>
<li>Show or don’t show a searchfield or configure another input field</li>
<li>Configure the search: post type, categories, tags, post title and content</li>
</ul>

Advanced Search Widget vs Dynamic Search Widget