This is the latest video of Matt Cutts about Breadcrumbs on search results and how to implement it on website. Google implemented it on search results but it is still on the early stage so there’s no fixed method or practice that is stated by Matts on the video. However, he emphasized that a “delimited links that accurately reflects the site’s hierarchy” might give a site a better chance to have breadcrumbs on search results.
Here’s the video: