WineBottler allows users to bottle Windows applications as Mac apps.
Wine has always been popular among Linux users for running Windows programs, but Wine is available for Mac, too - and now, free utility WineBottler can "bottle" Windows programs into separate application bundles that run as standalone Mac apps.
In other words, WineBottler is a tool similar to codeweavers' Crossover, where separate prefixes are created per app. However, WineBottler 'wraps' or 'bottles' the separate prefixes in an application bundle. WineBottler allows standalone (i.e., not requiring wine to be installed) applications to be created as well, by including the wine bundle inside the standalone application bundle.
