IconSettings, from the South African blog iPhoneZA, is an interesting hack that lets you set up one-touch buttons on your iOS device to access specific parts of the Settings app (like turning Bluetooth on or off, toggling Airplane mode, adjusting date & time, etc.) without going to the trouble of jailbreaking and using a tool like SBSettings. It's free, and takes only a moment to configure.
Pretty smart. Of course, you'll need to be connected to the Internet when you
use set up these things, since it's just a link on a webpage (the latest 2.0 versions of the bookmarks do not require connectivity after the initial config). But it's a cool implementation, and if there's a setting you find yourself having to browse through menus to adjust often, it might be worth setting up a bookmark or two for quick and easy access.