how to isolate image source tag

I have an rss feed that gives me something like this:

<description>&lt;br /&gt;
&lt;br /&gt;
buffalo protest&lt;br /&gt;
	&lt;img  
src=&quot;http://moblg.net/blogs/1015/thumbs/ 
moblog_a715627ec7b25.jpg&quot; alt=&quot;try 2&quot;  /&gt;
                </description>

I am wondering how with XSLT I can isolate the image source and get rid  
of all the proceeding and following garbage?
Thanks! Brooke