Software to listen to MP3 is available free of charge from many places on the Internet. An advantage to downloading the Real Networks' Real Player is that you can also use the same software to listen to MP3 music. The real trick to listening to music online is developing the patience for it. Everything online is coded in terms of bits and bytes, and eventually becomes a file. Text files are usually very small.
Images are larger files.
Audio files take up more file sizes for adequate reproduction of different tones, and video files are the largest, to compensate for both moving images and audio. Real Audio is used on the Internet because file size and resulting download time is small, and you can begin listening to the music stream while it downloads. Quality of sound is sacrificed for a smaller file size. Real Audio provides telephone quality sound. MP3 is used to create amazing CD quality sound, for a slightly larger filesize and download time.