I've been faced more than once with wanting to package up a collection of files, organized in folders, to share with my parents, who also run MacOS X. It might also come up in the future with a few friends who are considering Macs and not all of them are Unix-savvy. Most recently my dad and I needed to swap photo collections from Christmas.
With my Unix background, I naturally think we could all just tar and gzip collections. This has several shortcomings. One complete showstopper is that it requires using the command line to create an archive (decompresion is as easy as double-clicking). Another shortcoming is that resource fork information is lost (this will change when the next version of MacOS X Tiger is released: cp, tar, rsync will be HFS+ resource-fork aware). The lost fork is okay (and sometimes desired) for some filetypes such as JPG photos, but not for iView MediaPro photo catalogs and various other files which become useless if the fork is not preserved.
There might be free applications which allow manipulation of tared and/or gzipped files, but a quick search did not reveal anything that I wanted to ask my parents to download to help them create an archive.
For the photo swapping, I discovered that WebDAV was the way to go. WebDAV allows mounting of web server disk space as a drive in Mac’s Finder (same as .Mac’s iDisk) or Window’s Network Places/Internet Folders. I setup a WebDAV shared folder on my Dreamhost hosted website, where it is a feature, and then a short time later, my dad and I could both easily mount it and share files and folders of files via drag-and-drop. No archive file creation necessary. No FTP use necessary. Clearly an excellent solution.
However, I'm still keeping my eye out for alternatives. One I just learned about today: there is an application call BOMArchiveHelper in /System/Library/CoreServices/. If you drop a folder or file on that, the whole thing, including resource forks, are archived into a .cpgz file, a gzip compressed cpio file. If you double-click the file on another MacOS X system, the file or folder is restored. Unix users can also expand such a file by using gzip and cpio directly.
Another alternative, which amazingly didn't occur to me earlier, would be that it is easy to create a disk image from a folder of content. That would preserve resource forks, but would still involve using FTP or some other program to actually transport the file.
All in all, WebDAV was definitely the way to go, but it's good to keep in mind all the alternatives.