AccuRadio, Live365, WCPE's The Classical Station and New York's WQXR are all free online radio stations that play classical music. Classical music can also be accessed for free on Pandora, the popular music streaming service.
AccuRadio's classical music options encompass many genres and composers, with whole play lists devoted to artists such as Johannes Brahms and music of the Romantic period. Live365 also offers easily accessible and demarcated classical stations, including ones that differentiate Baroque from Chamber and Choral. On Pandora, listeners type in whatever classical music piece, composer or genre they desire to listen to, and the site returns appropriate recommendations.