Is it possible to share the desktop of the OSX86? is there some client for Linux/windows? (like windows RDP or x11vnc for linux)

Thanks

First question is not all that clear and probably is in the wrong forum. You can enable remote desktop on a mac under preferences/sharing/remote desktop. You need to enable the option for VNC. On the machine you want to control your osx86 machine with you need a VNC client. If you are just looking for a VNC client for osx - Chicken of the VNC is pretty good.

Gary

Well there is no such thing as "Apple Remote Desktop Client for Windows/(L)Unix", but the host service is a vnc server. So any vncviewer/client can connect to a OS X box
If you want to connect to a Linux box in OS X then go for chicken of the vnc, you can google it. If you want to connect to a Windows XP/2003/Vista box, then use microsoft's RDC client for mac.

I think this is clear enough

What about the other way around? I mean to enable Apple Remote Desktop services (in remote access in system prefs) and then use some kind of ard client to connect to it either from linux or from windows. (of course there's logmein service which works rather well and is free at the moment).