Simply drag a window to a side of your (right side) desktop to snap it or drag it to the top to maximize. If you drag it back to the last position, the last window size will be restored.
This simple application also works with multiple monitors. Remember that Aero Snap is still in its developing stage. While testing it here, found that some application window, example Ccleaner, shows no effect.
To run AeroSnap on your computer, you need Windows XP or Windows Vista. You need also .Net Framework 2.0 or higher.