It lets you download apk files from Google play store to PC without
worrying about country restriction and without logging in to your Google
account. The app requires you to enter the package name or Google Play URL for the app you want and after that, it will generate a download link for the apk file of the app.
Mind you, the site only works for apps that are available for free at the Google Play store. You are not allowed to download paid apps.
You can access the APK downloader at: http://apps.evozi.com/apk-downloader/
Below is a screenshot I took while trying to generate the apk of 2go chat application.
Right on the site, you can also download the Chrome plugin that lets you download apk files directly.