The program you use to encode to realaudio is called Real Encoder. You can get it at real.com. It's super easy to get and use. It's free too.
Some tips. You'll want to use these while you're working with RealEncoder, otherwise this will seem confusing (and if your printer's working fire her up). Note: these tips are PC-centric, but I'm sure it's similar on a Mac:
You do not want to be in wizard mode. Use the "advanced" mode. This lets you customize your settings a bit more. The wizard mode is completely inadequate, and the advanced mode is easy to use.
There are two ways to encode some audio to RealAudio. The first is from a wave file (a sound file already saved on your computer); and the second is "on the fly", directly from your tapedeck or whatever. This second is probably the way to go, certainly the easier of the two. You can just plug your tapedeck into the audio-in jack on your computer and realaudio will encode things in the time it takes to play it. Nice. To do this, in RealEncoder, from the screen that says "New Session - Advanced Mode" at the top, click "from media device" and "capture audio". On the right hit "save as" and put in your file name. Use file extension .rm.
After you do this you'll be in the screen that lets you type in the info about the file. This is the info that will be displayed while someone listens to the file. You can put it in now, but if you make a mistake you can edit it with a program that installed bundled with real encoder called "Real Media Tools"; as far as I can tell that's all this program does. You'll find that program in your startup menu under "Real Audio".
After you type in the song info you'll be at the second of the two realencoder screens. This one lets you set some compression perameters. On the right half of the screen you'll see some settings. They're self-explanatory. Set "music" if it's music, set "voice" if it's voice. I do everything at 28k, let me know if you find reason to do otherwise. Also, I've found that mono sounds a bit better than stereo, though this is also debateable.
Now press start to begin.
It'll say "encoding" and you'll see a levels meter on the screen. There's no way to edit the real audio file (at least not one I know), so you'll want to set this start point accurately, as you can't trim it later.
Then press "stop" when you're done. (One thing that drives me nuts about this program is there's a confirmation dialog "Are you sure you want to stop encoding?" before it'll actually stop encoding. So to get an accurate stop point I usually hit Stop way before I'm actually stopping, and then I just answer "yes" to the confirmation box when I want to stop encoding.)
You'll get a screen with some statistics. Nothing relevant as far as I can tell.
To do another one, hit file/new session.
That's it.
You can play your realaudio files from your computer (as opposed to from a website) just by clicking on them. Easy.
It's a myth that you need a special "realaudio server" to put audio up on your website. To get access to your webhosts RealAudio server, you usually have to pay about $10 extra per month. There is an advantage to this server, namely that lots of people can listen to the file at once. But if you don't expect that kind of traffic, you can put your audio up in a way that's free.
To put it on your website for free:
The principle is that your real audio files (.rm) are accessed through a "meta file", which is just a text file with extension .ram. The meta file is what you link to (you don't link to the .rm file).
Here's a sample meta-file
http://wrybread.com/noises/stealthis/clips/12.rm
http://wrybread.com/noises/stealthis/clips/1.rm
That's it. In this meta file, 12.rm is clip one, 1.rm is clip two. Easy. Load as many realaudio files into that meta file as you want.
Using this method, you can put RealAudio on any free website, like the one your ISP gives you or one of those other free websites like Geocities or Tripod.com. For a free website, I highly recommend using xoom.com, as they don't have that annoying ad that pops up all the time, and they give you 11 megs and FTP access.
If you're using a RealAudio server, substitute "pnm://" for "http://". Also, ask your webhost if they have any strange methods for how you have to write the rest of the statement. The idea is in the free method, you're streaming the RealAudio through http (like a really really big webpage), while the other way is streaming through a RealAudio server. The only disadvantage I'm aware of to streaming through http is that only a few people can hear the realaudio file at a time. If you're aware of other disadvantages, I'd love to hear about them.
If you're using frontpage or any other automated webpage maintenance program, a good tip is that you load the realaudio files to the website using your ftp program, as it's slow in frontpage. You put the metafile in your frontpage web though (since that's all you link to).
Here's another, slightly more advanced/confusing tip. To edit your metafiles from frontpage, configure notepad to be your editor of .ram files. To do this, in frontpage go to tools/options/configure-editors. Click "add", then in the "file type" window put ".ram"; in the "editor name" window put "Notepad"; in the "command window", hit the "browse" button and locate Notepad, which is in the c\windows directory. Once you find it, click on it, then hit OK, that's it. Now to edit a .ram file from frontpage all you have to do is click the .ram file and it'll send you to notepad, so you can write your .ram files. Easy.