The Voice of America, the United States' first official international radio service, began airing in 1942, during WWII. Since then, the service has provided a global audience with "a consistently reliable and authoritative source of the news," according to the VOA website. Besides news features, VOA also covers cultural, informative, and educational broadcasts; and the service is provided in 45 languages.
If you are interested in U.S. media history, the first place you may want to look is at the VOA organizational history, which is broken down by period, or at the historical highlights timelines.
Maybe you'd like to listen in on some of the archived broadcasts? In actuality, this may be difficult, if your broadcast of interest isn't brand new or at least 12 years old. However, the VOA does provide information on where certain broadcasts can be accessed (the National Archives being key).
The VOA list of programs offers links to many of the organization's programs and radio frequencies, which could be an excellent way to simultaneously teach English as a Second Language and current events, if you yourself are bilingual.
Similarly, you can check out streaming and on demand radio and film webcasts. On the other hand, if you are teaching English as a Second Language, select Learn English, which provides English-language broadcasts specifically designed for English learners.
One of the most unique, and potentially useful, features of the site is a pronunciation guide. Not only does the site write out location, organization, and historical and recent politician's names phonetically, it also provides audio files. So, for example, if you're teaching anything involving China, you can be much more confident discussing Jiangxi, Deng Xiaoping, Jiang Zemin, or Zhou Enlai in front of your class.