Although this is not a native solution for Orb under Linux here is a quote for somone running ORB under Linux "... currently run XP in a vmware session on my linux box just for ORB, and that's hardly a perfect solution". See http://forums.orb.com/viewtopic.php?p=20652
I have not come across anyone successfully running ORB under WINE.
I use ORB to stream audio and video to my PDA and will need this functionality as I move exclusively to Ubuntu.
An area that may be of interest is a Shoutcast server and NSV (NullSoft Video Streaming). Be warned that I have never set up Shoutcast on Linux but the Windows version worked very well for me. There is a native Linux Shoutcast server and NSV Linux utility. See the following links:
Shoutcast Linux Download: http://www.shoutcast.com/download/files.phtml
NSV Linux utility: http://www.scvi.net/nsv_linux.htm
Shoutcast recommended player - Linux/X Windows users should use XMMS
(What is NSV) http://www.scvi.net/whatis.htm
How TO NSV - http://gentoo-wiki.com/HOWTO_NSV_on_Linux
I suspect the downside of using this solution for video streaming is that ORB has the feature of adjusting (manual or auto settings) the stream rates for the target device. For example my PDA must have a lower stream rate (Kbps) than a PC or the video stutters and has buffer delays. I do not know if Shoutcast/NSV can do this.
As I stated I have not tried this solution on Linux yet. This is a project after I get Ubuntu displaying through my component video connection to my HDTV (come on ATI).