Streaming or Internet Radio is the term given to live radio that is delivered via the Internet in one continuous stream. Some Internet Radio stations operate only via the web, while other traditional terrestrial radio stations also offer an Internet Stream. Occasionally, Internet Radio is confused with Podcasting, however a Podcast is a distinct audio file that is actually downloaded to your computer rather and therefore can be listened to offline, while Internet Radio requires a persistent ant Internet connection.
Internet Radio has many advantages over traditional terrestrial radio but the reason it's become such a sensation is that you can tune in to a radio program that's being broadcast from the other side of the world. For example, when my father-in-law came over we tuned in to Cape FM - a local FM station in Cape Town, South Africa. And sometimes even if you want to listen to a local radio station (that you can tune in to on the dial) you'll find that tuning in on your computer means you'll get a static free sound.
Finding an Internet Radio station is as easy as visiting radiotime.com and either searching or browsing for a station. Once you've found the Internet Radio station you'll need to make sure you have the right software. In most cases you'll need either Windows Media Player (which comes standard in Windows but Mac users will need to download a copy from microsoft.com) or Real Player (www.real.com).
If you find yourself listening to lots of Internet Radio there are even programs that let you time-shift - or 'record' and listen to the programs when you want. If you're using Windows check out Red Button (http://radiotime.com/downloadcenter.aspx), or Radioshift (http://www.rogueamoeba.com/radioshift) for Mac OS X.
Internet Radio has become so popular that Grundig have even produced a product dubbed 'The Wireless'. It's a small radio like device that connects to your WiFi signal at home and lets you stream Internet Radio as if you were tuned into a terrestrial signal. At $499 it's a bit pricey, but if radio is your thing, then why not?