The podcast is <A HREF="http://news.yahoo.com/news?tmpl=story&u=/nm/20050409/wr_nm/column_pluggedin_dc">a radio-style show that is distributed over the Internet.</A> Podcasts have caught on like wildfire since they first emerged nine months ago. Listeners can pick from roughly 10,000 shows on topics ranging from religion to wine to technology, and media companies and advertisers are taking note.