BetterTouchTool!

Using Spectacle you can view multiple documents side-by-side, move windows to other displays, or even focus your full attention to a single task.

Aquasnap is a powerful window manager that helps you arrange and organize multiple applications on your desktop with minimum effort. It allows you to achieve maximum multitasking, especially if you own a high-resolution monitor or a multi-monitor setup.

ShiftIt is an application for OSX that allows you to quickly manipulate window position and size using keyboard shortcuts. It intends to become a full featured window organizer for OSX. It is a complete rewrite of the original ShiftIt by Aravindkumar Rajendiran which is not longer under development.

WinSplit Revolution is a small utility which allows you to easily organize your open windows by tiling, resizing and positioning them to make the best use of your desktop real estate.

Preme is a free software for Windows which lets you add cool desktop features and enhances the desktop functionality.

AltDrag allows you to move and resize windows much easier. When you have it running you can simply hold down the Alt key and then use your mouse to drag any window, and it doesn't matter where in the window you click. This is especially useful in netbooks, with respect to the small screen and touchpad. It simply allows you to do more with less mouse movements.

MagicPrefs is a free menubar and preference pane application for OSX which aims to improve the functionality and configuration options of the Apple Magic Mouse.

GridMove - A window management tool that can quickly arrange your windows into desktop grids.GridMove is a program that aims at making windows management easier. It helps you with this task by defining a visual grid on your desktop, to which you can easily snap windows. This program comes bundled with some predefined grid templates, that can be easily swaped, but also has ways of creating custom grids or sharing grids made by others.

HyperDock adds Windows 7 like features and more to Mac OS X.

Jitouch is a software that adds extra, essential, and the missing gestures to your MacBook Multi-Touch Trackpad and the new Apple Magic Mouse. The additional gestures in jitouch are thoughtfully designed and tested to let you perform simple tasks even more easily and using only one hand such as moving / resizing windows, zooming, minimizing, closing windows, quitting applications, changing spaces.

SizeUp allows you to quickly position a window to fill exactly half the screen (splitscreen), a quarter of the screen (quadrant), full screen, or centered via the menu bar or configurable system-wide shortcuts (hotkeys). Similar to "tiled windows" functionality available on other operating systems.

A tiny window management app for the Mac.

MaxSnap is a powerful window manager which lets you: