[Stream Recorder]

TubeMaster++ (http://all-streaming-media.com/record-video-stream/TubeMaster-freeware-open-source-stream-recorder-with-RTMP-support-Windows-Linux-MacOS.htm) for Mac OS is under development.

You can use command line tool rtmpdump (http://all-streaming-media.com/record-video-stream/rtmpdump-freeware-console-RTMP-downloading-application.htm), but you may have problems finding RTMP URLs for this utility. You may try rtmpsrv and rtmpsuck that come with rtmpdump.

Replay Media Catcher (http://all-streaming-media.com/record-video-stream/Replay-Media-Catcher-HTTP-RTMP-FLV-MP3-ripper-recorder.htm) works in Ubuntu Linux (I have no problems downloading RTMP streams in Ubuntu 9.10 using WINE) with WINE emulator, so it should work on Mac OS with Wine.


Any software that I have missed?

[Stream Recorder]

Replay Media Catcher (http://all-streaming-media.com/record-video-stream/Replay-Media-Catcher-HTTP-RTMP-FLV-MP3-ripper-recorder.htm) works in Ubuntu Linux (I have no problems downloading RTMP streams in Ubuntu 9.10 using WINE) with WINE emulator, so it should work on Mac OS with Wine.
You can indeed run Replay Media Catcher on Mac OS using WINE or WineBottler:
How to install and run Replay Media Catcher on Mac OS X (Snow Leopard)

[Stream Recorder]

Finally we have GUI stream recording software for Mac OS X:
Jaksta for Mac (http://all-streaming-media.com/record-video-stream/Jaksta-for-Mac-streaming-media-recorder-and-converter.htm) allows to download HTTP and RTMP streams from Adobe Flash Player.