I've recenctly worked with ErlyVideo servers. They allow you to manage RTMP streams so you can serve them in a web page using a flash player. They work pretty well but they have a big fail: then cannot be concatenated. What do I mean by concatenate? I mean that you cannot use an ErlyVideo server as source of other ErlyVideo. At least, in my tests, the result was a corrupted video output.
As there is a big lack of documentation regarding ErlyVideo configuration and deploy arquitecture, I decided to code a little application that would receive the rtmp streams from an ErlyVideo server and send them to other one. Using ffmpeg you can accomplish this job as it supports rtmp 1, but you need an application to manage all the ffmpegs and the streams and, once you are working on, it's a good idea to code some user interface. And this is the result: erlyconnect. It is a very simple application but it has been very useful.
As always, you can download it from the github repository at: https://github.com/diego-XA/dgtool/tree/master/erlyconnect/trunk There is a README file to see how it works. Please, let me know if you find some bug or just have some doubts about how it works.
ffmpeg supports RTMP if it has bee compiled to support it. I used the medibuntu and debian-multimedia repositories as the standard ffmpeg of ubuntu and debian do not suport RTMP.