BlueStacks is the simplest Android Emulator you can install on your PC. It does not run a traditional Android OS interface, installs directly onto a Windows PC, and allows you to run any app you have installed on your existing Android device. With BlueStacks you can install games like Angry Birds Space, social apps like Facebook and Seesmic, or free, internet-based messaging apps like Skype and Whatsapp messenger. BlueStacks is the winner of C|Net's "Best Software at CES 2012" award, so you really have nothing to lose by trying it out.
Simply download and install the BlueStacks emulator to your PC and you'll instantly be presented with a home screen that allows you to select which Android apps you wish to run. If you don't find the particular app you're looking to run, you can sync BlueStacks to your existing Android device with their Cloud Connect option. That way, anything that is downloaded to your existing Android device is immediately transferred to your PC's Android emulator.
This particular Windows-based Android Emulator requires at least Windows XP SP3, .NET framework 2.0, and 1 GB of RAM. BlueStacks is recommended to be installed directly onto Windows, and not in a virtual environment such as VMWare or VirtualBox.
Of course, not everyone has an Android device to pair with BlueStacks' Cloud Connect option. If you'd rather install a fast, fully functional Android OS emulator you should check out YouWave instead.