The Sims 2

If you have just The Sims 2, and you have never patched it, you can use the cheat intprop censorGridSize 0.

If you have an expansion pack or if you've patched the game, that cheat is disabled. You can use a mod like this: http://simsky.parsimonious.org/ensimsky.php to remove the blur.

Of course, under the blur Sims look as detailed as a Barbie doll, so you're not going to see much of anything if you disable the blur. You'll need to find more detailed skins if that's what you're looking for.