Looking for Mac guide? its here http://www.ruchirablog.com/how-to-install-on-whatsapp-on-mac/
On one of my previous guide I have explained you guys how to install and setup whatsapp on pc by using an android emulator called youwave. That article seems very popular and read by more than 500 people daily on this blog.
However there is one constrain on that method. It is that youwave is a commercial software and the free version only lasts for 7 days as I explained there. But you could always uninstall and reinstall after 7 days to get it working for 7 days more.
But now there is this software called bluestacks app player. Which emulates android apps better than youwave and most of all its free.