Now to emulate a Wii on a PC you will have to get some hardware and download some software.
The best software for Wii emulation is Dolphin.
http://www.dolphin-emu.com/news.php
I'm new to this but I can see already that this is the best software.
For hardware you'll need a very fast PC, like 2 or more GigaHertz and a very powerful Video Card.
You will also need a Wii wireless controller, a USB dongle, and a IR motion bar to put on top of your monitor.
If you already have a Wii then all you will need is a USB dongle device.
And better yet, if you have a laptop you might not even need a USB dongle as some Laptops have them built right in