Mac OS X's Archive Utility is a handy built-in tool, but it has some annoying quirks—like the fact that it automatically unzips files but leaves the original archive in place. Here's how to tweak its preferences more to your liking.
On the surface, Archive Utility doesn't look like it has any tweakable settings, because it doesn't stay open when it unzips a file. However, if you open it directly, you can tweak its preferences just like any other app. It's a little hidden, so if you want to edit them, you'll have to navigate to /System/Library/CoreServices/Archive Utility to find it (or, if you're using something like Quicksilver, just launch it like a normal app). Once it opens up, you'll be able to open its preferences from the menu bar as normal, and it has quite a few things you can tweak.
For example, you can check the box that says "Move Archive to the Trash" to delete a zip file automatically when you extract it in the Finder, which is helpful. You can also expand them to a different directory by default, or move a set of files to the trash when you compress them. It seems obvious, but many of you may not have realised it because of Archive Utility's odd opening and closing behaviour.
Get Rid of .Zip Files Once They're Expanded [Macworld]