The Thinking Atheist is a famous Internet Atheist who has his own Website and a YouTube account. Like TheAmazingAtheist and DarkMatter2525, his videos are used to promote Atheism and make fun of Religion. Unlike other other atheistic YouTubers though, The Thinking Atheist leans more towards proving religious people wrong rather than just making fun of them (that doesn't mean he isn't funny). He makes very good points and is educated in many scientific subjects such as Evolutionary Biology and basic Physics.
The Thinking Atheist also has a podcast by the same name, which is a call-in show that covers various subjects, depending on the episode. For a while, the podcast was the number one iTunes podcast under the religion category.
Here are some of his videos: