custom post taxonomy search form

There is 2 parts to what I am trying to do…

Found an awesome search form here which creates a dropdown menu of post categories and child-categories.

1. I am just learning custom posts and custom taxonomies and would like to modify this search form to do exactly the same thing with my custom post type, replacing the categories with my custom taxonomies.

2. If I can get step 1 figured out I would like to make this second search form available in my widget area. The one I am using now for post categories is in searchform.php and shows up in the widget area but I don’t know how to get a second search form to show up there without simply replacing the existing searchform.php

Here is the current search form…

<form role=”search” method=”get” id=”searchform” action=”<?php bloginfo(‘siteurl’); ?>”>
<div>
<label class=”screen-reader-text” for=”s”>Search for:</label>
<input type=”text” value=”” name=”s” id=”s” />
in <?php wp_dropdown_categories( ‘show_option_all=All Categories’ ); ?>
<input type=”submit” id=”searchsubmit” value=”Search” />
</div>
</form>

Just thought that I should point out that I am only really new to this stuff so I may not be able to follow instructions if they are too technical.

Thanks in advance