PC gaming may be approaching dire straights at the moment, but I don't think PC-in-a Wii casemod is going to prove to be the solution to the problem.
Enterprising modder mr.h has managed to stuff his Wii with all the necessary bits for a working PC, including a 1.3GHz Celeron CPU, 512MB RAM, and a 40GB hard drive, and has shown off his handywork on the A9VG forums. Of course those forums aren't in English, and even running it through Google translate doesn't help us understand the intricate details of the situation too much.
What is obvious is that the machine is running Windows XP, has a DVI output and its slot-drive still lights up nicely. It's almost certainly not powerful enough to play any of the more recent PC games, but as an exercise in engineering, it's a pretty impressive feat.
Here's a vid of the mod in action:
There's a full gallery of shots over on the A9VG forums, so if sticking the insides of a PC where they're not meant to go intrigues you, make sure you check it out.
[A9VG Forums - Thanks Leon!]