To record audio streams from MySpace you may use free RTMP recorder - MySpace MP3 Gopher. It can record RTMP .MP3 audio streaming only.

The only stream recorder/ripper that can capture flash video and MP3 audio stream (from embedded macromedia flash player) through the RTMP protocol is Replay Media Catcher.
Tutorial: How to Record RTMP and HTTP Streaming Flash Video and Audio with Replay Media Catcher
Video tutorial: How to Download Music and Videos from MySpace with Replay Media Catcher

More about RTMP stream capture/download software:
How to record rtmp:// flash video .flv stream from embedded Adobe Flash Player



Of course you can record RTMP audio stream with Direct sound recording software like free sound editor Audacity and record RTMP video streams from embedded flash player using Screen capture software, but with Replay Media Catcher you can save such streams without any quality loss. Besides Replay Media Catcher is very easy to use. All you have to do to record with it is to press "Start recording".