Go to Batanga.com and click on "Bachata" in the list of Free Latin Music Radio channels. Or, alternately, follow the link in the Resources section of this article.
Click the green "Play" button to start the radio station. A small window will pop up, containing the player. After a brief ad, the music will begin.
After one song has finished, the next one will begin. If you don't like a certain song, you can press the "Skip" button to hear the next one. Other features of the player include volume control, mood and star ratings, the option to purchase MP3s and ringtones of the songs, and a listing of the last three songs you heard, for reference.