Building Breadcrumbs Into Your WordPress Theme with a Free Search Engine Optimization Plugin - Build WordPress Yourself
Breadcrumbs are not only a good way to help site visitors navigate through your content. They also have great SEO value if used properly. Using WordPress SEO by Yoast, you can build breadcrumb functionality directly into your theme without much hassle. The theme user would then activate the breadcrumbs through Yoast if they chose to do so.