Karl, writing from the blog Athens and Jerusalem, has posted a long series on the "foundational falsehoods of creationism." Here is his video on transitional fossils.
He has a very good explanation of what a transitional fossil is as well as how many we actually have. The slides go past pretty quickly so you will probably need to pause the video to read them. The best line, regarding extinction: "practically everything that ever was, ain't no more."
Now playing: William Ackerman - The Opening of Doors