Whatsapp, the popular messaging client might get its first Windows Client that you can use on your PC. However, the work is still in progress and we will get to know if it makes it to reality with time.
So now if you are wondering how an app can work on a PC when it is not allowed to even work on WIFI only Tablets then here is the deal. The client emulates a mobile environment by using your phones IMEI number. It also gives you an option to choose your mobile operating system (Windows Phone, Android, iOS, Symbian or Blackberry).
The real added advantage of this is that Whatsapp will think that you are using the same phone and the app will work both on your phone and your PC.
I am pretty use that if this becomes reality, it will be successful even if it is a paid app. Whatsapp has a huge userbase and even with the availability of tons of messenger services its is the most successful.
The client development is open source and the work is in progress. So if you want to contribute in it, you can join the team. As of now the application can only test authentication. However, there is a previous version of the app available here which is available for the public. The screenshot posted by the developer is yet to release.