Visit Live 365 (see Resources below) and choose to hear one of the many live and free radio stations they offer. This site offers an extensive collection of music genres, including rap and hip hop, all completely free of charge.
Visit My Music Stream (see Resources below) to hear live streaming of rap music. You can also browse their selection by artist or look at their featured artists. There is music available for free downloads and also an online radio featuring a wide variety of music genres.
Visit Radio Row (see Resources below) for an extensive list of hip hop and rap radio stations. Choose the radio station you want to hear and click on it. You will transferred to the radio station, and after a quick registration where you will enter your email address, zip code, age and gender, you will be able to hear your selected radio station.