Networking Apples is like networking Linux and Windows - use TCP/IP. As for network file system compatibility I've got a little story.
One of the admin staff at work deleted some files from her hard drive because she had them backed up on a CD-RW. Well they suddenly needed the files, the CD-RW wouldn't load in the same system (Compaq Evo) or any other official system. They came to me (I've got a good rep - trust me
) as a last resort - "Would Linux help them recover the files?". So I took the disk to a spare workstation that I had running Ubuntu 5.04 as a demo for students. Magic - could see all the files but it only has a CD-ROM, used Samba (the Windows networking protocol) to connect to my Mac OS X Xserve and copied the files to my home directory. Went down to the Mac OS X Classroom and burnt a new CD-RW and returned the files.
So - you shouldn't have any worries with copying the old data across.