We are looking at NFS for a future release.
In the meantime, there is an NFS server, BeNFSServer, that was written by Andreas Huber. You can find it in BeWare, or check out his own web site:
Additionally, it is possible to write a BeOS file system plug-in that would mount NFS volumes, just as the BeOS can mount Macintosh hard drives. Be provides documentation regarding how to write file system plug-ins, so a wide variety of foreign file systems, including NFS, will likely be supported in the future.