How do you create an archive file which unarchives into the current folder? At the moment, if I create a TAR or ZIP file foo.tar - containing multiple files and directories - when I double click on the archive it creates a folder foo containing all of the archived items.

Is there a way to have an archive extract itself - when opened from Finder - so that the files are at the same level as the archive was?

I'm trying to distribute an archive which users can use to setup a USB drive with a custom icon etc, however this requires copying hidden files into the USB drive's root, so I can't just get them to "copy/paste from this network directory"
Unless I am mistaken (always a possibility), this behavior is set by the program extracting the archive file, not by the archive file itself.