I have a horrible time finding things here.
The first place I need to start is how to install the Cirrus package on my server. I can't seem to find what I need, where to download package and installation instruction. ( Linux / Apache server )
Why am I unable to find what should be obvious?
Codename Cirrus is a service hosted by Adobe. there is no "cirrus package" to install.
Flash Media Server can perform the same functions that Cirrus does, and more. you can download and install a developer edition of FMS. go to http://www.adobe.com/go/fms for more information.
And additional thing to consider is that FMS is not free.
While if i am not wrong , Cirrus is free to use. FMS is used for building "complex" multiuser applications and also for video streaming ( in video chats etc). While Cirrus can be used for lower end, simple multiuser applications, and thus would be lesser complex to code applications for. Additionally, Cirrus doesnot need any server side installation.