Newsgroups are an excellent way to find rare music and most ISP's feature a news server. Another use that is invaluable is in troubleshooting problems with your computer hardware or software i.e. Linux, by subscribing to particular news groups. There are many helpful groups out there and they are often populated with extremely talented individuals that are quite helpful. Unfortunately, using newsgroups is not very intuitive and at least for me I needed a little help getting started.
To gain access to your news server, you merely need to visit your ISP's home page and do a search for news. If they provide this service, they will have instructions on how to set up an account and also how to log in. Usually, you get an allotted amount of bandwidth per month for "free". My ISP offers 2 gigabytes per month (not including headers) through GigaNews.
My favorite newsreader for binaries is Forte Agent, they have a free version. For messages, I prefer Microsoft Outlook or Outlook Express.
There is also a possibility that the ISP you have will offer newsgroup access, but they will have filtered out binaries (such as MP3's) as these are often illegal files. In that case, you would have to seek out an independant news service and yes, then it is an additional charge.