If you wish to sell bitcoins, you can use one of the exchanges like Coinbase (USA) or Bitstamp (Europe) or many others.
There are many ways, and new ways each day, just check out Bitcoin Trade Wiki and Coin Map
Bitcoin is a public digital currency that can be sent directly from person to person. It is a new, secure and free technology that enables
Bitcoin uses peer to peer technology to operate with no central authority; managing transactions and issuing bitcoins are carried out collectively by the network. Through many of its unique properties, Bitcoin allows exciting uses that could not be covered by any previous payment systems.
For more information visit bitcoin.org or search online for Bitcoin.
