Small Office Network Including OSX and XP Computers

[john-o]

Not sure what you "got", but the primary limitation, as I'm guessing you've discovered, is the lack of read/write support for NTFS on a Mac. There are several options available online that supposedly make it possible, but none are foolproof, imho... Macs and PCs can share files in recent versions of OS X via enabling "Windows" sharing in the Sharing pane of System Preferences. Again, though, it's not as obvious and simply as one might want or expect. Let us know more details about what you're doing, and I'm sure others will chime in.