I wanna do that. So far I've don the following without any success.

- Downgraded my iTunes in mac mini from 7.xx to 6.xx (version 7 not compatibe)
- Added music
- From settings / shared I shared the whole library
- Opened iTunes share from preferences
- Open canola --> finds my library
- Select library and badaboom Canola crashes
- Select only 25 songs to shared library
- Canola finds library and the songs, and when I start to play a song --> error

Then I tried some upnp server, wich understands iTunes xml files. And When I try to open the library the upnp server crashes. I think the server was allegro media server. What next. My songs are located in a nas drive that is connected with RJ45 to modem, and n800 is connected with wlan to my home network. So what have I missed. I would like to play the songs with Canola if possible.

Are these iTunes Store music, or ripped from cd music? I've heard there's problems with linux and drm'd music.

Well mostly ripped from various sources. No DRM here. I just thing that what if the library is just too big for n800 to handle. In that case I need to make a playlist for iTunes which updates frequently smart playlist are great for that. Besides that it will be a breeze to manage playlist when you can connect to mac mini with vnc. But still:

I would like to share the whole library, and do it with free software. So any advice would bee good. And last but not least, I like canola so I want to use that as a player.

Try using Mediastreamer instead of Canola to connect to your uPnp-Server on the Mac Mini. Works like a charm here (altough using Twonkyvision on XP as uPnP-Server).
I can even use Mediastreamer to remote control the playlist and volume of my Noxon 2 Radio for iPod - this is absolutely awesome. Basically, the Noxon plays music from the uPnP-Server - using Mediastreamer, I can then add new songs to the playlist of the Noxon (and see the album art of the song that is currently on air :-). The N800 acts as a Media Control Point in this case. Mediastreamer als includes a volume control - I can therefore wirelessly control the colume of the Noxon (even using the hardware +/- keys of the N800).
Insanely great, extremely impressive...hehe

I really can't see my library on mac mini running osX tiger with media streamer. Canola sees it but hangs. ATM i am using I tunes share, but it's the same with allegro media server.

I use fuppes on my fedora box. Its built from source.
If you can build it on OSX, it may solve your problem.

http://sourceforge.net/projects/fuppes

Twonky Media. Pay the 30 bucks and everyting cool.

Oh and I don't think protected AAC files work with the N800.

Twonky was the answer I now can use the canola to play my media

BUT:

If anyone knows a twonky substitute for free then let me know. ATM I am so broke that I cannot buy twonky.

this is a nice archive exporter
http://www.fireflymediaserver.org/
and as an added benefit itunes users can access your archive

(it works with canola as well)

-best
-gwak