They make binary versions of shared libraries for the codec they use for their streaming audio and video. In theory there's everything you need to write a "save this stream as a wave file" (or connect to lame to emit mp3), but the Mac version requires CodeWarrior (!) and so I couldn't experiment. It's planned that future versions will build with GNU and Apple tools, so hopefully I can get there some day.
Conclusions: the site is hideously complex and confusing. What a bestial design. But major kudos to Real for completely opening this up. In theory (licensing issues aside) it should now be perfectly possible to write an xmms plugin, for instance, that plays Real streams.