It's possible, but I think it's too much work. Yappari relies heavily on being in an N900 and I think it's even easier to write another client from scratch than make Yappari work in something else. There's something called WhatsAPI (google that) which is a set of libraries to make a WhatsApp client in other platforms. I think they use PHP and/or Python. If you want WhatsApp in your PC just install BlueStacks (google that) and install the official WhatsApp client and that's it.