When transferring directories between my Linux desktop and Mac OS X Laptop as tar.gz archives, I often run into the problem that the unpacked files on the OS X system won't show up in the Finder -- not even when I restart the Finder (this happens at least on 10.3).
Apparently the problem is caused by some sort of issue with the .DS_Store file. Removing the .DS_Store file (only possible from the Terminal) lets the files eventually appear in Finder.
Mac OS X Hints
http://hints.macworld.com/article.php?story=2007112102521062