Bitcoin is the first and most famous cryptocurrency. It was conceived by Satoshi Nakamoto in 2008 and release early 2009. Satoshi has since disappeared so it was likely a pseudonym of one or more other people. As of August 2013 the total market cap of Bitcoin exceeds 1.4 billion US dollar. There's a wide range of startups that try to make money with Bitcoin related products.
See coinwiki.info for more information about Bitcoins and cryptocurrency in general.