I've been an Air Video user (running the Windows server) for a long time now. I just got around to trying the Air Video Server for Linux alpha 6 and it works great.
The process of getting this working on my Linux machine (running Fedora 16) was quite involved and I had to find, patch, and manually compile mpeg4ip 1.6.1. Just in case anyone else is in the similar situation I have provided a step-by-step guide for this which includes Avahi (Bonjour/mDNS) configuration and automatic start/stop of the server on system startup/shutdown.
The guide is here: http://www.dunkley.me.uk/2012/04/i-use-excellent-air-video-to-stream-non.html
I hope this proves useful.